Electronic Commerce : Factors Involved in its Adoption from a Bibliometric Analysis

This article presents findings of a study that aimed to identify key factors in the adoption of e-commerce. The study involved a bibliometric analysis of statistical information from 408 scientific publications related to the theme, registered in the Scopus database, through a structured search equation. The collected records were used to calculate bibliometric indicators of quantity, quality and structure. Additionally, an analysis of increasing, decreasing, and emerging thematics was carried out to identify the topics of greatest interest on this subject. Findings indicate that this is a prolific research field, in which the fastest growing topic is the study of e-commerce adoption in small and medium sized enterprises in emerging economies. The analysis also revealed the current use of new models to evaluate adoption factors. That is the case of the Technology Organization Environment Framework used as an alternative to the Technology Acceptance Model--which remains the most widely used. Likewise, Structural Equation Analysis was found to be one of the most frequently used options for statistical analysis in the publications studied. A research agenda intending to contribute with directions for further research in the area is presented at the end of the article.


Introduction
As part of the tools of the new millennium to generate competitiveness in organizations and foster the use of information and communication technologies ICT, electronic commerce or e-commerce emerged.This type of trade has been increasing over time and more and more organizations are generating these communication channels with the customer to enhance trade relations [85].Overall, e-commerce is changing the nature of trade worldwide; however, this revolution is developing at different rates in different areas of the planet [208].At present, its most relevant influence is taking place in Asia, USA and Northern Europe [20], [144], [206].
In addition to its outstanding advance in developed countries, e-commerce is being used more and more in emerging countries where the level of its acceptance is rapidilly increasing.Due to the changes occurring in the way shopping is being carried out worldwide, commerce has passed from happening through direct contact between people to taking place through intangible means and a variety of alternatives, offered based on the customer's needs, in order to obtain goods.As a result, organizations that have traditionally offered products for sale through traditional channels, are finding better alternatives to make handsome profits through virtual ones.
Understanding how e-commerce technology adoption behaves in the social and economic contexts in which it has not been studied, is of paramount importance to contribute to future research in this field, as well as to provide the business sector interested with channels different from the traditional ones to enter new markets.Nonetheless, given the sociocultural differences existing among developed and emerging nations, and due to every process of adoption responds to different cultural, social, and political dynamics, the study of technology acceptance in diverse contexts becomes challenging.Consequently, this study intends to examine the approaches, topics, and variables that have emerged in the exploration of e-commerce technology adoption in emerging countries in order identify the existing factors that influence such adoption in different economic, social, and cultural contexts.
Decisions about adopting technologies like e-commerce are influenced by aspects such as the relative novelty of these types of innovations and the greater uncertainty associated to the implementation of new technologies at large.In this regard, several studies have inquired about the factors that influence e-commerce application and found that they vary in terms of object of study, as well as the social, cultural, and economic contexts where this technology is adopted.Such variety of influencing factors has hindered establishing generic models to permit an adequate evaluation of the issue.Accordingly, this research study sought to examine and discuss trends and developments in the analysis of the factors involved in the adoption of e-commerce, led by two main research questions: What are the tendencies in the study of e-commerce adoption factors?What are the most researched topics in this field of knowledge?
The causes that motivate people and enterprises to find out the factors that move the business sector to adopt electronic commerce are diverse.In this regard, [11] claims that the most important benefit that promotes e-commerce adoption in the business sector is the generation of customer trust, while its most significant barrier is lack of electronic payment systems.On the other hand, [13] state that e-commerce has become a very important opportunity among small and medium-sized enterprises (SMEs).SMEs executives have realized that e-commerce allows them to introduce innovation in the market and increase their competitive advantage in a more efficient way.
Regarding pragmatic motivations, an adecuated identification of the factors involved in the adoption of e-commerce at the time of implementing it within a given enterprise context permits incrementing the productivity and profits of corporations and facilitates the generation of strategies consistent with the needs of the implementation environment.Consequently, awareness of the factors that influence e-commerce adoption will make its implementation easier and more likely to be successful for an enterprise.Carrying out research about this matter is thus very important as it would enable the assignation of resources on the factors and variables identified as a priority at the occasion of implementing e-commerce [97], [129], [132].
Regarding the method, bibliometrics have been chosen because it allows a holistic view of the researched context of a specific theme [154]; providing significant data about topics, authors, journals, countries and the most productive and influencing institutions; and supplying information about current trends in the issue and its impact on a given context [58].Therefore, bibliometric studies are considered to offer valuable starting points for new research on emergent themes [67].Considering the qualities of bibliometrics, we have chosen this research method to study the factors of e-commerce acceptance.We considered that it would enable suitable access to the research context of the topic, permitting the identification of the main approaches, and the authors that have made the most outstanding contributions in the generation of new models and methodologies to study it.
A bibliometric study was thus utilized in this analysis as a tool to facilitate the identification of tendencies in the adoption of e-commerce.Several indicators for the analyzed field were defined and a dynamic of keywords that permitted the identification and selection of 408 journal articles was developed.The inquiry led to the revision of the main publications on the topic, with the intention of having a holistic perspective of the factors that are most frequently associated to the adoption of e-commerce.We expect that such perspective will serve as a referent for new studies on the evaluation of adoption factors, giving access to a richer number of theoretical sources, permitting an integral vision of the results Since 1997, when the White House launched the Framework for Global Electronic Commerce, a perception of the need to implement suitable policies for the development and growth of digital systems necessary to strengthen the free exchange of goods, services and information via Internet emerged.In this regard, the referred framework sought to strengthen e-commerce through four general principles that aimed at adopting an unregulated approach that would prevent undue restrictions to electronic commerce.The private sector would ideally lead the process recognizing the qualities of the Internet to develop it on the basis of a global context [43].Despite the fact that almost 20 years have passed since the adoption of the regulatory framework, electronic commerce has not yet developed as envisaged within the global context.As a consequence, developing countries have basically failed to adequately adopt ecommerce.However, research has been conducted to study the factors that enable and promote its adoption [19], [21], [27], [52], [76], [86], [93], [96], [99], [119], [149], [176], [179], [204], [207].The existent literature has allowed conceptualizing e-commerce and typifying it according to some characteristics.Table 1 groups the categories and applications of e-commerce defined by different authors in the literature: B2C (Business to Customer).
Negotiation of products or services through electronic advertising buy, sell and secure payment systems between customers and organizations.
B2B (Business to Business).It is the market transaction among businesses, governments and other organizations in a reliable way between them.[115].
C2B (Customer to Business).It is the online transaction where consumers begin the commercial operation with companies.
C2G (Customer to Government).Online interaction where feedback is given to the government by pressure groups or individual sites.

B2G (Business to Government).
It is the online interaction where feedback is given from business to government and non-governmental organizations.

G2C (Government to Citizen).
Online interaction through which the government offers domestic services, such as local government, national government information and tax information transactions.
Non-Business E-commerce.
Organizations and academic institutions, civil, religious, social and governmental organizations use e-commerce to reduce costs of operations.[193].

IntraBusiness ecommerce.
All internal activities usually performed on an Intranet.The activities are to sell corporate products to employees, online training and cost reduction activities.[193].
It includes providing related information between business and government procurement activities.
Information to citizens or, at best, simple electronic services such as downloading electronic forms.[183].
Source: prepared based on the sources mentioned in the table.

Adoption Factors of E-Commerce
E-Commerce is defined as a channel for any type of transaction, including offering products and services through the Internet, which, despite its advantages, has not yet managed to persuade a greater proportion of users to carry out transactions through this means of shopping [23].In this regard, several studies have shown that the rate of consumer adoption for e-commerce is low in emerging economies and in micro, small and medium sized enterprises (SMEs) compared to developed countries [10], [18], [54], [70], [73], [99], [141].Therefore, it has been considered important to conduct studies that examine the trends and developments in the identification of factors that encourage the adoption of e-commerce.
Academic and research studies have sought to explain the phenomenon of adoption of e-commerce with the goal of properly encouraging its use from various fields.For example, through the theory of diffusion of innovation, [65] an integrated model of the adoption of e-commerce for small enterprises in emerging economies was developed.Through this model, it was possible to identify determinant factors for the adoption of e-commerce involving perceived usefulness, perceived compatibility, perceived risks, perceived ease, and perceived complexity, which are defined in Table 2.
By the same token, [45] utilized the notion of orchestrating resources to study the process of adoption of e-commerce; findings from this study suggest that the prevailing competitive environment of each phase results in a capacity of specific coordination that develops through actions focused on resources.Another approach examined the dynamic competition between traditional retail companies and retailers on the Internet, using dynamic games theory [161], [101].
Other researchers have used the descriptive research design with statistical techniques to identify the same factors.
As an example, a regression model was used in [21] to anticipate the adoption of e-commerce.In that study, all variables except the business experience of the company were found to have a significant contribution to explain the phenomenon.
Regarding the focus of the papers analyzed, a study of issues such as gender to identify its impact on the adoption of e-commerce showed that it slightly influences its implementation in SMEs.[39].A qualitative approach on the same subject showed that both organizational and environmental contexts and attributes of innovation influence the adoption of e-commerce [19].Other studies on e-commerce investigated issues such as consumer behavior, analyzing the factors that influence the type of products / services purchased online [152] or cultural values of the individual behind the buyer's decision [38].Finally, study [61] considered the performance of companies operating exclusively on the Internet, called e-companies or dotcoms, analyzing factors that are intrinsic to the Web site, such as accessibility, web presence and utility.
Table 2: Description of determinants of adoption of e-commerce, according to Elahi and Hassanzadeh [56] Factors Description

Perceived usefulness
The extent to which an individual believes that using a particular system will improve his/her performance in an activity [49].It is also defined as user perception that the use of technology will improve its performance over previous technologies [47], [48].On the other hand, perceived usefulness is the determinant component of cognitive behavioral intention, while attitude represents the affective component [48].For [197], perceived usefulness offers a more detail explanation of why an adoption does not occur.Finally, perceived usefulness, a TAM factor, is usually operationalized as an attitudinal variable in research [92].

Perceived compatibility
The degree of consistency of the technology with values and beliefs, past and present, as well as with the needs of adopters [80].According to [167], it is related to the degree to which the adopter is able to incorporate an innovation into his or her life.Perceived compatibility gives the idea of how using a system fits with values and habits of the person at the time of completion of the measure [49].

Perceived risks
The fulfillment of the conditions of the transaction and online security [156].It is one of the essential theoretical supports when uncertainty is present, as characterized by the absence of physical contact as in the case of online environments [146].Liiterature has showed that perceived risk influences the adoption of technologies [63], [146].

Perceived ease
The extent to which the prospective user of a technology expects its use not to involve efforts [49].

Perceived complexity
The extra effort that comes with the application of an innovation, achieving minimum values when the complication of its application is greater [166], [168].Reason for which, the ease in handling a computer system should positively influence the perception of their utility [6], [139], [177], [197].
Source: prepared based on the sources mentioned in the table.
On the other hand, [158] identified critical success factors for e-commerce including: adding value, focusing on a niche, expanding, maintaining flexibility and segmenting geographically, adopting the right technology to handle a critical perception, providing exceptional service, creating an effective connectivity, and understanding the culture of the Internet.Meanwhile, [50] studied internal and external organizational factors that may impact the use of Internet among SMEs, finding aspects that enable organizations to be self-efficient through technologies related to marketing use and perceived competitive pressure.The study carried out by [49] analyzed factors that prompt the adoption of e-commerce, examining the influence of perceived usefulness by consumers, and proposing the addition of five sources of income associated with the Internet: price advantage, variety of assortment, value of products, perceived convenience and access to information.In addition, [9] studied behavior in e-commerce adoption finding a significant correlation between perceived compatibility, perceived complexity, perceived observability, perceived uncertainty, among other factors analyzed.
Electronic commerce continues to be an emerging distribution channel even in developed countries.As a result, varied studies have been conducted to identify influencing factors in the adoption of e-commerce, and its implications for big contexts, first level economies, and large size enterprises.According to [168], a study conducted in Kuwait presents a model of online payment trust that reveals the impact of four external factors: personal innovation, tendency to trust, familiarity, and presence of third party seals over the intention of using an online payment through the mediation of three endogenous variable factors: pleasure, risk, and costumer trust.Costumer trust and pleasure are two important factors in the adoption of online payment.By the same token, [133] examine the factors that affect e-commerce adoption in the Arab states.Five countries are represented in this study: Saudi Arabia, Qatar, Kuwait, United Arab Emirates, and Yemen.Findings reveal that knowledge is the most important factor that influences the adoption of ecommerce mediating between costumer perception about the risk and their confidence to adopt it.
In fact, for large enterprises in the First World countries [165] analyzed the combined influence of environmental, technological, and organizational factors that determine e-commerce adoption.The study provides proof that competitive pressure discourages e-commerce adoption in the long term.The findings of this study also reveal that the development of consumption patterns, the technology availability of the market forces, the global reach of the enterprise, and its competences in innovation, continuously favor e-commerce adoption.Meanwhile, [59] showed that organizational, technical, and environmental barriers, as well as technology external factors have affected two initial variables of the Technology Acceptance Model (TAM) that includes perceived usefulness and facility.Likewise, the relations found in the TAM were confirmed including the impact of usefulness and perceived facility over attitude, the impact of attitude over intention, and the impact of intention over actual use.
The study conducted by [175] demonstrates that in developed countries security and privacy are the main aspects that encourage enterprises to adopt e-commerce channels, and consequently consumers to develop confidence in the digital environment.Electronic commerce will be useful in the current management practice, in the design of business policies and strategies, and in the exchange of information between organization executives and leaders.E-commerce Bibliometric analysis has thus been proven a methodology that permits a quantitative identification of tendencies and behavior on a specific area of study through a variety of indicators, depending on the factors of interest identified for a particular research study [198].The bibliometric approach is mainly based on the search of quantitative characteristics of the topic studied: features of research publications, such as article titles, key words and phrases; authors, including their institutional afiliation, coauthors and reputation; and books and journals, including titles, topics and country of origin [75], permitting the identification of patterns useful for research advance and scientific development [148].In this article, a bibliometric analysis of the factors involved in the adoption of e-commerce was made from the data of academic publications reported by the SCOPUS database.SCOPUS provides tools to manage information, and meets other criteria such as the amount of citations and accessibility, which make it one of the most used databases in this type of analysis in the literature [77].Besides its accessibility, SCOPUS was selected in this study due to being considered a valid, reliable, and timely source of academic information, which makes it the largest database regarding citations and abstracts from peer-reviewed literature and highquality sources in the Web [83], [124].On the other hand, the researchers intended to address a data base different from the one used in the studies mentioned (WOS).In addition, high levels of correlation in their reported bibliometric indicators have been found between Scopus and WOS, which make the two data bases statistically comparable and stable.Thus, the indicators of production and scientific quality would equally support findings generated by either of the two data bases [16].
Subsequently, a search equation was defined per the object of bibliometric analysis; i.e., the factors involved in the adoption of e-commerce.For this purpose, key terms equivalent to electronic commerce (e-commerce -electronic commerce) were considered as search criteria along with stems equivalent to the term adoption (appropriat * -adopt *).Those key terms were searched in the title and keyword fields, with no restriction of time for a broader horizon of analysis (taking as cutoff date, items recorded in Scopus until April 1, 2017).Tests with 7 equation options, which Among the indicators calculated in this study, there were statistics about activity (amount) that permitted visualizing the state of the art, within which the number and distribution of publications, productivity, dispersion of publications, and collaboration in publications are included.Likewise, there were impact indicators (quality), used to assess the incidence of authors, papers, and / or journals in a specific area or discipline [28], [53].Finally, there were structure indicators that allowed measuring connections between different authors and publications [170].
Some of the indicators permitted to evidence the factors involved in the adoption of e-commerce in terms of quantity, indicating items with higher impact such as the years with the highest production, the most representative journals, and the most prolific authors in the area.The measurement of publication quality through impact (in terms of number of citations) is widely accepted, mainly based on what the Frascati Manual and the Organisation for Economic Cooperation and Development (OECD) propose for the measurement of Research and Development (R&D) activities, and the analysis of research systems and scientific specialization both of researchers and countries [53], [95], [130], [140], [163].Based on the previously mentioned, the number of citations of an article has been taken as a point of reference for the calculation of quality indicators.By the same token, quality indicators facilitated to explain authors' impact, and reasons for journals and articles to be the most outstanding and cited [95], [140], [163].Structure indicators allowed to observe the behavior of working nets on the theme [70], [210].Finally, trends in the study of the explored field were analyzed through the observation of the behavior of the key words, which permitted identifying increasing, decreasing and emergent fields in the area [198].

Findings
The results of the analysis are presented in this section based on the indicators proposed in the methodology.The information has accordingly been grouped in four categories: quantity indicators, quality indicators, indicators of structure, and research trends in e-commerce adoption factors.

Quantity Indicators
Based on the obtained search equation, the bibliometric quantity indicators calculated for the topic of Electronic Commerce are laid out in this subsection of the findings.decreases steadily to present a new increase in 2010, this being the year of the highest increment with 39 published articles.From 2011 to 2016, a steady decline in the number of publications has been showing, which may be an indication that the identification of factors of adoption of e-commerce had its process boom between 2001 and 2006 in the theoretical realm and retaking known models of technology acceptance.Later, we have seen that publications have focused more on identifying adaptations of adoption models according to the particular socio-cultural, economic and demographic contexts.In conclusion, we observe that research tendency in the topic has focused on more specific alternatives, opting for the evaluation of factors in particular business dynamics (small and medium-sized business).Such evaluation has been based on the use of quantitative models in agreement with the Diffusion of Innovation Theory, in which inquiry about the validity of the factors of those models and their pertinence in the successful adoption of ecommerce has been conducted.
To determine the journals with major impact in the field, it is necessary to identify the ones that publish the 80% of research studies on the topic [117].However, regarding the topic of this article, that percentage is disseminated among 62.07% of the journals (87 journals) that publish on the subject; therefore, it is not possible to present a traditional graphic grouping the journals with the highest production.It was thus considered appropriate to take the 10 main journals that publish on the topic as a reference, selected on the basis of the number of articles that address ecommerce adoption factors (the number of citations from these studies has not been considered yet).Accordingly, Figure 2 presents the ten journals with the largest number of publications related to the field of study., where technology issues involving e-commerce are discussed, ranging from platforms and Web services, to knowledge models for e-commerce for both the environment and the company, as well as peculiarities of the different applications of this technology [118].The second journal, with 6 articles, is the Industrial Management and Data Systems, in which papers about the social, cultural, organizational and cognitive impacts of e-commerce technology and advances in organizations worldwide are published [120].The third journal with most publication is the Journal of Internet Commerce, with 6 articles, which "promotes greater access to high quality presentations at conferences and workshops on computer fields" [121].The fourth publication, is the Electronic Commerce Research and Applications Journal [57], [122]  To continue the analysis of the cumulative percentage of publications per journal, Figure 3 permits to conclude that there is no Pareto Law, due to 62.07% of the journals published 80% of the items.Therefore, we proceeded to separate the percentage of journals per quartile, obtaining the following results: (1) 9.20% of the journals published 25% of the articles; (2) showing a significant increase in the proportion, 24.14% of the journals published 50% of the articles; and (3) the remaining 52.9% of the journals published 75% of the articles.This shows that on the subject of adoption factors of e-commerce, knowledge is dispersed among several journals related to the area of Information Technology and Communication, and there are no publications with a significant concentration of studies on the field.In connection with the number of publications by journal, the cumulative amount of publications of the top ten authors (see Figure 5) shows that there is no Pareto Law, since 63.46% of the authors published 80% of the articles.Given this situation, we proceeded to separate the cumulative percentage of publications for the first ten authors, by degree of relevance, obtaining that: (1) 12.18% of the authors published 25% of the articles; (2) 34.62% of the authors published 50% of the articles; and (3) 59.0% of the authors published 75% of all articles.The information collected reveals an equitable distribution of articles per researcher; i.e., in terms of number of publications no author stands out.By applying natural logarithm to each of the axes, the law of productivity was obtained for journals (Figure 6) and for authors (Figure 7).This law postulates that productivity does not follow a linear but logarithmic distribution; it can thus be inferred that "the more published articles an author has, the easier it seems for them to produce and publish" [124].In conducting this analysis, the authors of a given set of publications are distributed in three levels of productivity: the small producers (log n = 0), the media producers (1> log n> 0) and the large producers (log n> 1) [125].Figure 7 shows the squared value of the regression coefficient of the adjustment on cumulative number of articles against the natural logarithm of journals, being greater than 0.9, demonstrating a proper fit for the proposed model for productivity.The law of productivity was also verified for authors in the field.Figure 7 presents the results obtained with respect to this law.The graphic shows a determination coefficient greater than 0.8 confirming a suitable adjustment for the proposed model for productivity.As mentioned above, the authors analyzed have an average level of productivity.Finally, it is worth noting that 48% of the records obtained from the search equation correspond to articles and 40% are papers presented at conferences.The participation of other types of documents on Electronic Commerce is 7% (see Figure 8).Accordingly, one could say that the dissemination of academic and research findings in this field is mainly concentrated on publications in refereed journals and participation in conferences that allow greater interaction and associativity between authors.
In addition, classifying these publications by area of knowledge shows that most of them are located in the area of Computer Science (50.0%) followed by the area of Business, Management and Accounting (38.9%),Engineering (18.1%), Social Science (15.9%), and Decision Science (13.4%).This shows that the main interest has focused on developing better computer systems (software, apps, etc.) that allow greater acceptance of e-commerce in contrast to the area of Business and Management, which pursues a greater ownership of technology towards improving profitability levels and the use of such means for companies to sell their products and for consumers to make their purchases.

Quality Indicators
This section presents the bibliometric indicators for quality, calculated for the factors of adoption of e-commerce, according to the defined search equation.As mentioned above, quality indicators are closely related to the publication impact; in other words, the number of its citations, [53], [69], [95], [130], [140], [163], [198], [210].Based on quality indicators, it was possible to find the ten authors with most citations on the subject (see Figure 8).Within those ten are Almeida V.A.F.et al., who tops the list with 168 citations.Their publication dates to 1999, and it is an investigation that proposes a methodology for characterizing and generating e-commerce workload models.In the paper, the authors first introduce a state transition graph called Customer Behavior Model Graph (CBMG), used to describe the behavior of groups of customers who exhibit similar navigational patterns.Following, a set of useful The consecutive authors in the graph with the highest number of citations are the researchers Kevin Zhu and Weiyin Hong, who have 151 citations each, of an article whose methodology was based on multi-nominal logistic regression, demonstrating that technology integration, web functionalities, web spending, and partner usage were significant adoption predictors.The model showed that these variables could successfully differentiate non-adopters from adopters.Further, the migration model demonstrated that web functionalities, web spending, and integration of externally oriented inter-organizational systems tend to be the most influential drivers in firms' migration toward ecommerce, while firm size, partner usage, electronic data interchange usage, and perceived obstacles were found to negatively affect e-commerce migration [82], [126].This study provided adequate tools for the implementation of strategies that would adopt Internet services in a cultural environment different from that of developed economies.
The following researcher within the top ten in the list is Licker P.S., with 148 citations recorded.This article from 2005 shows that the effects of network externalities influence the based on perceived organizational e-readiness (POER) and perceived environmental e-readiness (PEER) [127], [134].The quality indicator does not have any similarities with that of quantity, because none of the 10 authors with the highest number of citations is part of the 10 authors with the highest number of publications (compare Figures 4 and 8).
Regarding impact, the journal with the highest number of citations is International Journal of Electronic Commerce (IJEC) [90], with 148 citations.The IJEC is a quarterly journal devoted exclusively to electronic commerce, which aims to provide an integrated view of the field by presenting approaches to multiple disciplines.It does so through the publication of topics such as the effects of e-commerce market, the transformation of the organization with e-commerce, business models in e-business, management and supply chain collaborative commerce, the co-creation in ecommerce, social network analysis, and e-commerce in the globalization of business, among others [136].
Information and Management, with 78 citations, stays in second place.This journal serves managers, professionals, database administrators, and senior executives of organizations, which design, implement and manage Information Systems Applications.The major aims of the journal are (1) to collect and disseminate information on new and advanced developments in the field of applied information systems; (2) to provide material for training and education in administrative data systems; (3) to encourage further progress in information systems methodology and applications; and (4) to cover the range of information system development and usage in their use of managerial policies, strategies, and activities, for business, public administration, and international organizations [135].
Below in the list is the European Journal of Purchasing and Supply Management with 72 citations.This journal fulfilled its 30th anniversary making contribution to research.It provides integrated information systems and how these can be developed and used effectively, to manage information and knowledge that may lead to more effective results in the organizations' vision [137].
Out of the 20 journals with the highest number of citations in the topic, 62.50% pertain to Scopus Q1, 16.67% to Q2, 8.33% to Q3, and about 12.50% are not ranked in the quartile due to being Proceedings (see figure 9).This fact evidences that the journals with the highest quality are the ones that report a higher number of citations in the topic.Besides that, among the thematic areas published in these journals, two approaches stand out: (1) a Business Management approach, with the following subtopics declared in Scopus: Business and International Management, Management of Technology and Innovation, Strategy and Management; and (2) a Systems Approach with the following subtopics declared in Scopus: Computer Networks and Communications, Information Systems and Management, Human-Computer Interaction, and Information Systems, which evidences the interest in both fields of knowledge about publications related to e-commerce adoption factors.Finally, the bibliometric analysis identified that the topic of Electronic Commerce has been studied since its inception in 1996, when 3 citations were recorded.In the years 1998 and 1999, the thematic one obtained a significant increase in the number of citations, with 47 in 1998 to reach the highest number of citations, 104, in 1999.The article that achieved this amount of citations is the aforementioned Methodology for Workload Characterization of E-commerce Sites showing that the most outstanding authors of the thematic have contributed the findings with greatest value in the field [125] (see figure 10).

Indicators of Structure
Structure indicators measure the connectivity between publications [138], the authors, and areas of knowledge; these are often associated with the construction and analysis of social networks, which consist of nodes (vertices) and links.In the case of a bibliometric analysis, nodes are authors (people who research and publish their results) and links represent co-authorships.Thus, from the analysis of these networks, it is possible to identify outstanding The analysis of structure indicators arose 863 authors in the field, and evidence that, on average, each author has published with 2 other authors (2,125).Additionally, the network density was found to be close to zero (0.002), which shows that the strength of connections between the authors of the entire network is very low.This could indicate that the dispersion of production is significant.In addition, the group subnets formed between its nodes (authors) is also significant since they have a degree of clustering of 0.622.This does not however imply connectivity since heterogeneity (0.671) was found to be greater than said grouping--which implies that some subnets tend to look like a star.This shape means that there is a central node in the subnet connected to the others, which can be a bridge for connections between authors while their disappearance could cause the isolation of nodes with which it has links; i.e., an author is the one who serves as a connection with others to work the different subject area knowledge.
The typical explanation about cohesion for the effect of network position on knowledge outcomes is that centrality provides individuals with timelier access to richer and more diverse information, increasing the extent to which they learn from their network and their potential to synthesize and recombine this information into novel ideas [153].At the other extreme of the spectrum, the cohesion perspective views ties as pipes through which information and knowledge flow and characterizes network position in terms of centrality; that is to say, the extent to which an individual is well connected, both directly and indirectly, to others in the network.
Networks are not merely a representational form of social relations.Instead, research in network theory posits that the structure of relationships affects the opportunities and constraints of individual action and their outcomes.Networks affect opportunities for action [68]; additionally, the collective actors as well as the relations that they sustain are the building blocks of social networks.
Table 1 also shows the cumulative structure indicators in two periods (1996-2005 and 1996-2017), with the purpose of analyzing the evolution of the network of authors over time.There, there is an increase in the number of authors (number of nodes), number of independent authors (number of isolated nodes), and number of isolated subnets (number of isolated components).However, the growth rate of the nodes is much larger than that of the isolated nodes and connected components.Therefore, there is a decrease in the dispersion of isolated subnets and independent publications (variations of component indicators connected by nodes and components isolated by nodes respectively).Evidently, authors who are adhering to the field, do so by means of already formed networks.
In this sense, the subnets have been increasing in size and decreasing in density, which is reflected in the evolution of the degree of clustering and the diameter of the network.In spite of this, a slight increase of the density of the network reflects that the new authors are related to some few authors of the subnet to which they were connected, and as a consequence the expected characteristic distance has not undergone variations.
Another characteristic evidenced in this network of authors is that there is only one link of the shortest path that connects all the nodes of a network (1,210) and that in turn, the maximum distance between any pair of nodes of the network is equivalent to 4, which corresponds to a typology of networks of internal knowledge management, used to maximize the application of individual knowledge to the objectives of the organization.These networks evolve through thematic mapping of experience within the organization, and environments conducive to knowledge sharing [143].
In Figure 11, the most dynamic topics in the analyzed period are evident.Accordingly, SMEs becomes the keyword that has the highest recurrence and therefore the context in which e-commerce is being researched the most.Such research shows that e-commerce is being implemented in the SMEs, through the use of information and communications technologies (ICT) to facilitate its access [21], [98], [110], [120], [125], [126], [147].In this regard, it is clear that promoting e-commerce in the sectors of small and medium sized enterprises has become a national development policy in some countries [40].Similarly, in Latin America, there have been studies that have identified factors that reflect greater impact on the adoption of electronic commerce, namely the company size and their level of maturity in the implementation of ICT [54].On the other hand, [112] discusses the importance of the use of e-commerce for the development of small and medium sized enterprises as it constitutes a source of competitive advantage.Other studies examine the effectiveness and impact of government policies to support the use of e-commerce and propose some recommendations [106].The study of [159] concludes that the rate of adoption of e-commerce in SMEs is directly related to the rate of adoption of ICT.Meanwhile, [147] presents evidence that SMEs are more prone to the adoption of electronic commerce, and have more financial and technological resources as well as greater external pressure to be part of such trade.
The second recurrent keyword in Figure 11 is adoption, which evidently refers to the adoption of e-commerce.It indicates that research has explored the effort that is being made in small and medium-sized companies in emerging countries to incorporate e-commerce to improve performance [94], [116], [120], [123], [125], [147].Among the analyzed research, various factors of adoption of e-commerce are mentioned, and those that have to do with organizational and financial issues stand [4], [7], [26], [27], [72], [141], [196]; for example, [81] states that the Organization for Information Ecology (OIE) is an important factor for the adoption of e-commerce and the paper proposes a model that integrates this vision to previously known factors.With respect to B2B e-Commerce, studies show that foreign aid is crucial to increase the levels of its adoption, and that SMEs whose managers completed higher education are more likely to adopt it [112].On the other hand, [125] examines, through the TOE Framework (Technology-Organization-Environment), the factors that allow the adoption

Keywords_Dynamics
of B2B e-commerce in Europe; as a result, the proposed model found seven factors including the development of technology, technology integration, the size of the company, the obstacles, the level of education, competitive pressures, and socio-business collaboration.The study also explained that the exponential growth of the Internet population encourages the adoption rate of e-commerce in different parts of the world.It is noteworthy that the adoption of B2B e-commerce in an emerging country was simulated with a model in which the size of the company, the business experience, the experience of Internet use, the amount of computer equipment, and the income and percentage gain of the company were considered as explanatory variables.This model showed that all variables except the business experience of the organization have a significant contribution to explain the adoption of electronic commerce by SMEs; in fact, it revealed that the number of employees and business experience of the company is negatively related to the adoption of electronic commerce [21].
With regards to Technology Acceptance Models, the Technology Acceptance Model (TAM) as well as the Theory of Diffusion of Innovation (IDT) and the TOE framework have been used in order to explain the adoption factors in small and medium sized enterprises in emerging countries [14], [19], [37], [64], [125], [176].On the other hand, the study of e-business is specifically addressed by [184], showing the trends in research in this field; findings of this study also indicate that this field of research is multidisciplinary and is evolving to integrate with the supply chain as well as with specialized technologies in line [35].The TOE framework identifies three contexts that can influence the use of a technological innovation in the field of organizational psychology [181]: technological context, organizational context, and environmental context [3], [84], [111], [113], [115], [191].The TOE framework has been successfully used to understand the key factors of information systems that affect adoption [84].
Likewise, [47] introduced the Technology Acceptance Model to explain acceptance in the use of information technologies for the first time.This model is based on the Rational Action Theory (RAT), a psychological theory that intends to explain behavior based on intention.According to the RAT theory beliefs influence attitudes, which lead intentions, generating conduct [8].The Technology Acceptance Model adopted this relation and applied it to the acceptance of information systems by users [1].The TAM includes two primary predictors: the easiness of use and the perception of usefulness.Behavior intention acts as an independent variable, which in RAT is supposed to be tightly linked to actual behavior.This way, the TAM establishes the causal relations between perceived usefulness, perceived easiness of use, attitude towards use, and actual use of technology [105].Finally, [145] argues that the TAM can explain user behavior through a broad spectrum of end user computing technologies.
Regarding the Supply Chain Management research has been conducted on its current and future state, focusing on the use of ICT, e-commerce and supply chains, and specifically on the type of technology being adopted, adoption factors, benefits, and barriers affecting the use of e-commerce as a way of innovation for logistics service providers [164].In addition, [101], [162] conducted studies where B2B interactions were investigated in the supply chain showing that this tool improves its management.Finally, [25], [171] conclude that although the rate of e-commerce among providers of logistics services is small, those which have adopted e-commerce have seen a high level of benefits and a contribution to the development of e-commerce within the company in general terms.
Figure 12 displays the fields of research in e-commerce that are in growth, decrease, and increase; this analysis is based on the periodical behavior of keywords, allowing to identify trends for both the topics with a growing and less interest of researchers, and making evident the new topics of interest in the area studied.According to Figure 12, the research fields that are growing for the selected search are small and medium sized enterprises, adoption, developing countries, model of technology acceptance, e-business, information and communications technology (ICT), management of the supply chain, Theory of Diffusion of Innovations, ICT adoption models, and mobile commerce.These results point to the identification of e-commerce adoption factors in SMEs as an option to improve their position and competitiveness in the market.In addition, the graph pinpoints models that are being used to examine the factors that motivate the adoption of e-commerce such as Theory of Diffusion of Innovations and Technology Acceptance Models, and statistical analysis through Structural Equation Models.Regarding the fields in decline, the graph shows that these are electronic markets, consumer behavior, social theory, economic analysis, electronic data interchange, ICT adoption, optimization of mobile services, and tourism industry.Finally, the nascent fields are Technology-Organization-Environment framework (TOE) and adoption of systems.
Based on the identified themes, further research on the matter should focus in differentiating influencing factors in the adoption of e-commerce, based on the economical and social context of users, as in the case of variables such as private security and perceived risk, which usually differ according to the context.In addition, findings suggest researching about differences that can occur when population divisions such as gender, intention of using this channel for the shopping/buying of products, and the influence of culture in the adoption of e-commerce are made [97].In the same vein, research studies should be linked to theoretical models of innovation adoption and diffusion, with the aim of having stronger statistical support in the analysis of variables.An approach based on the structuration theory, which focuses on studying social phenomena with the intention of understanding the interrelation between individuals and society [66] is one that could be useful in further research.On the other hand, theories of a stronger explanatory nature could be utilized to explain the role of culture in the generation of individuals' perception, which would lead to a better comprehension of the relationship between information privacy and culture [132].Finally, one of the flaws in research in this field is the lack of studies with a longitudinal standpoint that could provide a better perspective in the process of adoption of electronic commerce from a followup of determined moments along the process.
Based on the previous graphic, Table 4 groups adoption factors of electronic commerce through the analysis of the articles containing the key term adoption.The title of the article has been included to provide the focus and context of the article and facilitate constrast between the identified adoption factors.Following, we will provide an agenda intended to guide future research and provide recommendations about the important factors to be considered in the adoption of e-commerce: Nickels and Kwun [137].
The relationship between ecommerce adoption and organizational culture.

2006
Organizational cultures with an emphasis on external orientation and flexible structure, adhocracies, are typified by leaders who are innovators and risk takers.This paper proposes a research framework for exploring the proposition that organizations exhibiting higher levels of an adhocracy culture orientation will also exhibit higher levels of e-commerce adoption.Pearson and Grandon [147].
An empirical study of factors that influence E-commerce adoption/non-adoption in small and medium sized businesses.

2006
The results indicate that SMEs most receptive to adopting e-commerce have the financial and technological resources, see e-commerce as useful for their firms, and feel external pressure to integrate e-commerce into their organization.Reddick [162].
Government E-commerce adoption: A study of Texas counties.

2006
For counties that had an e-commerce Website, improved customer service was the most commonly cited impact.The most frequently reported management barrier to ecommerce adoption concerns problems with transaction or convenience fees.Having an e-commerce Website was associated with being a large county government.Siyal, Chowdhry and Rajput [180].
The adoption of E-commerce by overseas Sindhis: An empirical study.

2006
The results indicate that income level education level and exposure to the Internet were significant predictors in explaining the rate of adoption of e-commerce by overseas Sindhis Tarafdar and Vaidya [184].
Challenges in the adoption of E-commerce technologies in India: The role of organizational factors.

2006
The role of top management, aspects of organization culture, characteristics of Information Systems professionals, and organization structure.
B2B e-commerce adoption decisions in Taiwan: The interaction of cultural and other institutional factors.

2006
Results indicate that organizational, industrial, governmental, and cultural factors do indeed influence B2B e-commerce adoption decisions.In addition, the nature of the cultural influence is dictated by industry conditions.MacGregor and Vrazalic [118].
Strategic alliances and ecommerce adoption in regional SMEs: A comparative study of Swedish and Australian regional SMEs.

2007
The results showed that membership in a strategic alliance was associated with the rating of importance of ecommerce adoption factors, but only for specific sections of the SME population.The results also showed that these associations are not universal, but differ from location to location.Qi and McGilligan [159].
An investigation into Ecommerce adoption profile for small and medium-sized enterprises in Bury, greater Manchester, UK.

2007
Results show that the adoption rate of information and communication technology (ICT) and e-commerce in Bury is a step ahead of the UK in general.
Adoption of e-commerce: A decision theoretic framework and an illustrative application.

2007
Extensive literature review that revealed a number of factors or attributes that either act as drivers or barriers of e-commerce success.
SME Adoption of e-commerce in the Central Okanagan region of Canada.

2007
The study found significant factors that differentiated adopters and non-adopters of e-commerce included technological opportunism and readiness, owner experience with computers, support within the organization, relative advantage and compatibility.Wu, Zhang, Xing, Dai and Du [202].
A study for understanding ecommerce adoption in China's service SMEs from web usability perspective.

2007
This paper supports that web usability is the core of ecommerce adoption and states that understanding China's service SMEs adopting e-commerce requires studying web usability first.
E-commerce adoption of travel and tourism organisations in South Africa, Kenya, Zimbabwe and Uganda.

2008
The African websites were found to be generally informative but lacked interactive facilities for online transactions.It is recommended that these African organizations evolve their websites into marketing tools to capitalize on the potential Internet market.Peng and Kurnia [149].
Exploring the national context in Electronic Commerce adoption in developing countries.

2008
This paper recognizes the unique national context of the developing countries and argues that the national context factors can have significant impact upon EC adoption by organizations in developing countries.
Factors affecting e-commerce adoption in the electronic manufacturing companies in Malaysia.

2008
The multiple regression analysis results indicate that relative advantage, compatibility, complexity, observability and security appear significant.Relative advantage and compatibility have positive and significant influence on EC adoption whereas complexity and security have negative effects.This study also revealed a non-significant relationship between trialability and e-commerce adoption.Elahi and Hassanzadeh.[56].
A framework for evaluating electronic commerce adoption in Iranian companies.

2009
The result indicates that there is a significant positive relationship between degree of electronic commerce adoption and stages of electronic commerce development in the companies.
A conceptual model of factors affecting e-commerce adoption by SMEs in China.

2010
A multi-level conceptual model of these aspects of factors affecting e-commerce adoption in Chinese SMEs is proposed on the basis of innovation diffusion theory, technology acceptance model, institutional theory and strategic orientation theory.
Perceived compatibility and the adoption of B2C Ecommerce by non-buyers.

2010
The results have demonstrated the importance of perceived compatibility as a significant factor to foster nonbuyers' adoption of electronic business-to-consumer ecommerce (eB2C).Hwang [86].
An empirical investigation of normative, affective, and gender influence on ecommerce systems adoption.

2010
The moderating effects of gender are tested based on the socio-linguistic literature.As expected, the influence of social norms is stronger in the female group while the influence of enjoyment is stronger in the male group.
Understanding electronic commerce adoption in bruneian SMEs: A replication of the Application of TAM and perceived strategic value models.

2010
Two out of three perceived strategic value factors are significant, whereas four out of five adoption factors are a significant determinant of e-commerce.
Impeding barriers for Ecommerce adoption in Libya.

2011
Electronic commerce (e-commerce) has found its way into many organizations globally, numerous studies reported that its adoption have been constrained by inefficient operation and lack of infrastructural facilities.Govindaraju and Chandra, [71].

E-commerce adoption by
Indonesian small, medium, and micro enterprises (SMMEs): Analysis of goals and barriers.

2011
This paper reports a study on goals and barriers of ecommerce adoption by Indonesian SMMEs.Further, it is found that human resources and source of information factors are the most significant barriers for e-commerce adoption by Indonesian SMMEs.Chen and Holsapple [35].

E-business adoption research:
Analysis and structure.

2012
The study reveals that e-business adoption research is a multidisciplinary issue.Particularly, e-business adoption in organizations is moving toward an advanced stage in the evolution continuum.Van Huy, Rowe, Truex and Huynh [169].
An empirical study of determinants of E-commerce adoption in SMEs in Vietnam: An Economy in Transition.

2012
In this research, the authors adapt the Technology-Organization-Environment (TOE) framework and test a model of e-commerce adoption including numerous internal and external factors identified in empirical studies.

Perceived Benefits and Ecommerce Adoption by SME Travel Agents in Developing
Countries: Evidence from Egypt.

2013
This research aims to examine the perceived benefits of an advanced level e-commerce adoption by Egyptian travel agents.Results indicate that marketing and competition benefits, essential benefits that support strategy and development, and business efficiency benefits all positively contribute to decisions that lead to an advanced level of ecommerce being adopted.Al-Somali, Gholami and Clegg [12].
An investigation into the adoption of electronic commerce among Saudi Arabian SMEs.

2013
The authors find that the level of e-commerce implementation has yet to mature and customer readiness for Internet shopping must improve before e-commerce reaches the levels of maturity seen in other regions of the world.Bertea and Zait [24].
Perceived risk vs. intention to adopt E. commerce -A pilot study of potential moderators.

2013
The purpose of this research was to investigate potential moderator variables which could change the relationship between perceived risk and the intention to buy online.Although no moderation effect was proved, partly due to the homogeneity of the investigated pilot population, fear of uncertainty and trust in e-commerce were found to be antecedents of perceived risk in e-commerce, making perceived risk a mediator between these two variables and the intention to buy online.

2013
This study undertakes a full examination of the e-businessadoption area, focusing on 618 journal articles that deal with e-business adoption.These are coded and analyzed along multiple dimensions, including journal distribution, units of analysis, data source regions (geographic focus and economic focus), research method, and research theme.Additionally, by comparing their results with those of prior studies, new trends in e-business-adoption research are detected by linking the five dimensions, practical implications for e-business adoption researchers are also provided.Machfud and Kartiwi [121].E-commerce adoption by Indonesian small agribusiness: Reconsidering the innovation-decision process model.

2013
This paper discusses and proposes Rogers model incorporating all elements of the innovation-decision process model including the stages of innovation-decision and its influencing factors such as prior conditions, communication channels, characteristics of the adopter, and the perceived characteristics of e-commerce to a better understanding on e-commerce adoption process.Sila [178].
Factors affecting the adoption of B2B e-commerce technologies.

2013
The objective of this study is to analyze the factors affecting the adoption of Internet-enabled business-tobusiness electronic commerce (B2B EC) and test their applicability in different contexts.The results showed that all of the contextual variables, except country of origin, influenced some of the adoption factors.The study shows that the technology-organization-environment (TOE) framework provides a strong foundation for the study of B2B EC.Wymer Regan [204].
Influential factors in the adoption and use of E-Business and E-commerce Information technology (EEIT) by and medium businesses.

2013
A number of differences were found among SMEs based on demographic characteristics, particularly size and industry-sector.
Determinants of e-commerce adoption amongst SMMEs in durban, South Africa.

2014
Using the Diffusion of Innovation Theory (DOI), this paper examines the determinants of e-commerce adoption by South African SMMEs in the Durban area.Findings reveal that relative advantage and compatibility are the only DOI variables that significantly influence the decision to adopt e-commerce in Durban.Specifically, improving information exchange with customers, easier access to international markets, expansion of business reach, reduction of costs of maintaining up to-date company information and improving information exchange with suppliers are significant factors that inform the decision to adopt ecommerce in Durban.
Determining e-commerce adoption level by SMEs in Indonesia based on customeroriented benefits.

2014
This study proposed a number of Indonesian SMEs' ecommerce adoption levels and their ranks based on customer-oriented benefits.Analysis result shows that Indonesian SMEs can be classified into four levels of ecommerce adoption based on customer-oriented benefits.
An Empirical Study of Factors Affecting e-commerce Adoption among Small-and Medium-Sized Enterprises in a Developing Country: Evidence from Malaysia.

2015
The findings show that e-commerce adoption within Malaysian SMEs is affected by perceived relative advantage, perceived compatibility, managers/owner's knowledge and expertise, management characteristics, and external change agents.
A qualitative study of business-to-business electronic commerce adoption within the Indonesian grocery industry: A multi-theory perspective.

2015
This study shows the usefulness of complementarily deploying several adoption theories, and offers important theoretical and practical implications for organizations as they extend their supply chains globally.
Factors affecting e-commerce adoption among SMEs in Ghana.

2016
The results indicate that government support has the greatest direct impact on intentions to use e-commerce.Managerial support and the influence of enabling and regulatory conditions also play a vital role in stimulating SME e-commerce adoption in Ghana.The results also show that Ghanaian SMEs tend to imitate successful firstmovers to avoid the risks that attend e-commerce technology.
An empirical analysis of the adoption barriers of ecommerce in small and medium sized enterprises (SMEs) with implementation of technology acceptance model.

2016
The results showed that organizational barriers, technical barriers and environmental barriers as external factors on technology has effected on two starter variables of technology acceptance model that includes usefulness and perceived ease and these predicted relationships are confirmed.In addition, expressed relationships in the Technology Acceptance (TAM), including the impact of usefulness and perceived ease on attitude, impact of attitude on Intention, and finally impact of Intention on actual use was confirmed.Jafari, Khatibzadeh and Taj-Bornaee [91].
A multi-factor trust management system based on confidence in M-commerce environment.

2016
Trust plays an important role in the development and profitability of users in mobile commerce systems.In order to estimate the amount of trust, the variety of trust management systems have been proposed and implemented.One of the main challenges facing these systems is the types of attacks that threaten them and their impact on trust evaluation.In this paper, studied four important attacks including new comer, Sybil, on-off and reputation squeeze and also proposed a multi-factor trust management system based on confidence.The proposed model is simulated and results show that mean absolute error (MAE) is decreased.Kuswanto and Sudarsono [108].

Perception of factors influence on intention of adopting E-
Commerce with the business value as intervening variable.

2016
The objective of this study is to analyze the perception of the factors that affect the intention of adopting e-commerce by micro enterprises through the business value.The factors include relative advantage, ease of use, security, cost, managerial characteristic, external pressure, managerial behavior towards e-commerce, and trust.The results show that relative advantage, ease of use, managerial characteristic, and trust influence on the business value, while security, cost, external pressure, and managerial behavior towards e-commerce do not.Next, the business value influences on the intention of adopting e-commerce.Thanji and Vasantha [187].
A study on drivers and barriers of consumer adoption towards E-Commerce offerings for education.

2016
Findings: Majority of the consumers are pushed towards adoption due to time saving aspect while lack of required technical skills stands out as major barrier.
Walker, Saffu and Mazurek [199].13 shows the ones identified by the authors consulted in chronological order: The figure 13 allows to observe that during the last decade the studies about the identification of e-commerce adoption factors have been prolific and demonstrated their evolution around diverse organization characteristics.It is worth emphasizing that in the early years (2006 and 2007) varied factors involving both organizational and technical aspects were identified.Research in the field has gradually advanced, going from studies that explored the technical factors to studies based on technology adoption and acceptance models (TAM), as well as on consumer behavior models (TPB) (2007-2010).Research has as well included studies intending to explain the identification of these factors through an articulated model (TOE), and the ones that have identified the importance of a suitable governmental structure as a mediating factor that impels e-commerce adoption, especially in developing countries (2010-2016).Based on Table 4 and Figure 13, we next generate a research agenda intending to guide the study of adoption factors in e-commerce in order to demolish barriers around this technology to access the benefits that it promises.1.In first place, key aspects identified in the adoption of e-commerce are the role of the organization managers, and its organizational culture and structure.In this regard, organizations that count on financial and technical resources and have a flexible structure are more likely to taking risks and adopting e-commerce as part of their strategy.
2. Regarding the factors that stimulate e-commerce adoption in small and medium sized enterprises, findings point to the importance of considering technological opportunism and readiness, owner experience with computers, support within the organization, relative advantage, and compatibility [182].In addition, factors related to the national context have been found to have a significant impact in the adoption of e-commerce in certain countries.In countries such as Malesia and Indonesia, for example, e-commerce has been affected by perceived relative advantage, perceived compatibility, manager/owner's knowledge and expertise, management characteristics and external change agents.
3. Some results point out the importance of considering gender factors influencing e-commerce adoption.In this regard, the influence of social norms is stronger in the female group while the influence of enjoyment is stronger in the male group.Regarding B2B e-commerce adoption, some findings indicate that education level along with exposition to Internet use become significant predictors to explain the rate of adoption of this new technology.
4. Regarding research methodologies to study e-commerce adoption factors, statistical analysis, structural equations, as well as models such as TAM and theories like DOI, findings of some studies indicate that marketing and competition benefits, essential benefits that support strategy and development, and business efficiency benefits all positively contribute to decisions that lead to an advanced level of e-commerce being adopted.
5. Finally, future work to be considered includes a meta-analysis or a systematic review of literature about the adoption of e-commerce in SMEs in emerging economies, in order to propose a model for it in accordance with the economic and social context, and the limitations of SMEs in such economies.On the other hand, a comparative analysis among the most used models in the evaluation of the adoption of e-commerce (Technology Acceptance Model; Theory of Planned Behavior; and more recently the technological framework model, Technology-Environmental-Organizational Framework, is recommended to put forward a unified integrative model that compiles the findings in this research field.
We would like to note the importance of making e-commerce a value generating tool in small and medium sized enterprises, considering that such enterprises constitute the 95% of the productive apparatus in developing countries.This could be achieved and consolidated through the strengthening of organizational processes, building flexible structures that permit an adequated level of risk in order to introduce this type of technology.In addition, since ecommerce adoption is a social process, the study of the factors that allow it in the market of small and medium sized enterprises should integrate qualitative and quantitative research methodologies.

Conclusions
The analysis evidenced that the study of factors of adoption of e-commerce is developing significantly in small and medium sized enterprises, due to them being most prone to the implementation of this commercial channel.Current studies are being conducted in a focused way in emerging economies, because it is in these countries where SMEs make up a large proportion of the business sector.With regards to the slow adoption of e-commerce in small businesses, they are attributed to various barriers that relate to perception of adoption and economic obstacles to invest in technology.A decisive factor in adopting e-commerce is perceived ease, this being a predictor of behavior for consumer purchases via the Internet.On the other hand, increased acceptance in the adoption of technology by consumers can be positively affected by the use of smart phones, because of its flexibility and ease of use, in addition to the installed capacity of banks to support credit card transactions, while still being complex, given that purchasing power becomes an important factor to prevent consumers from making transactions online.
It was possible to observe through the bibliometric analysis that great importance on the research field of e-commerce lies currently on the analysis of the processes of adoption of e-commerce in small and medium-sized companies in emerging countries, using robust models as the TAM, the Theory of Planned Behavior (TPB), and more recently, the TOE.On the other hand, statistical analysis through structural equations stands as the main form of analysis of information reported by research on the factors influencing the adoption of e-commerce; this is important because it constitutes a statistically robust tool to shape these factors and their role in the use of e-commerce.Finally, a strong interest is emerging in implementing e-commerce in the management of the supply chain through logistics providers, using it as an alternative that has resulted in benefits and high levels of productivity in companies.
With respect to the factors that favor the adoption of e-commerce, the following were identified: prior use of Information and Communication Technology (ICT) in the company personnel, the existence of national policies in support of ecommerce, the size of businesses, the level of maturity in the implementation of ICT in organizations, the provision of financial and technological resources for the implementation process of e-commerce, external pressure to be part of this type of trade, and possibilities for external assistance (advice or support) to implement e-commerce platforms.
Regarding the classification of e-commerce by type of transaction (see Table 1), the analysis indicates that the mode reporting more research is business-to-business (B2B) in emerging economies, which is linked to the growth in Internet users in emerging countries.This evidence the need for the business sector in emerging economies to increasingly adopt E-commerce among their strategies for market expansion.Among the factors that influence this process are the growth of the company, business history, recognition of the company by consumers, and the marketing strategies they use to reach potential customers.
It was observed that decreasing research fields (electronic markets, consumer behavior, social theory, economic analysis) focus on macro variables in the context of adoption of e-commerce.The decreasing interest of researchers on those aspects of the study of the adoption of e-commerce may be explained by the fact that research has (1) focused and specialized in particular factors that determine their use, and (2) oriented towards the perception and satisfaction of the business sector and consumers with the variables involved in its adoption.Among those variables are perceived confidence, attitude towards the use, and perceived ease of use, perceived usefulness, safety, and innovativeness.
The bibliometric analysis results show a growth in interest in the subject since 2001, 2006 being one of the most productive years with 38 published articles.With respect to publications, the Proceedings of the International Conference on Electronic Business (ICEB) was found to be of significant interest, compiling disclosures made within the framework of the conference, where technology issues involving E-commerce are discussed.That includes platforms, web services, knowledge models for e-commerce for the environment and for the company, as well as the peculiarities of the different applications of this technology.
The analysis of the law of productivity concludes that there is no Pareto Law, since 71.48% of the journals published 80% of the items, so we proceeded to separate the percentage of journal by quartile, obtaining that 8.20% of journals published 25% of the articles; presenting a marked increase in the proportion, 28.52% of the journals published 50% of the articles; and finally, the statistics showed that 64.45% of the journals published 75% of the articles.This indicates that knowledge is scattered in various related scientific journals in the area of Information Technology and Communication and there are no academic journals that have a significant concentration of studies on the topic of ecommerce adoption factors.
The author with highest productivity was found to be Robert MacGregor, Associate Professor in the School of Informatics and Computer Science at the University of Wollongong in Australia.His research expertise covers the area of information technology (IT) and electronic commerce (e-commerce) in small and medium enterprises (SMEs).
Regarding the impact of publications on the subject, Chwelos, P (2001) tops the list with 489 citations; the paper presents results of an investigation of a parsimonious model that postulates three factors as determinants of adoption of electronic data interchange (EDI): provision, perceived benefits and external pressure.The authors conclude that external pressure and readiness are considerably more important than perceived benefits.The journal with the greatest impact is Information Systems Research (ISR), with 164 citations.ISR is an international journal that focuses on theories, developments and research on information systems in fields such as organizations, economy, and society in general.

Limitations
Among the main limitations of bibliometrics is the lack of a solid theoretical background supporting the construction of bibliometric analyses, which implies difficulties to generate strong enough indicators and leaves the inclusion and interpretation of a large part of the indicators to the criteria of researchers.On the other hand, dependence on a particular data base causes the risk of leaving aside journals which might be too recent to have been indexed or journals that have decided to get indexed in a different data base, which reduces the scope of information to be accessed.
The definition of systematic search equations, requires the analysis of information structures in data bases, which hinders the search in unpublished papers or papers published in lower quality journals or events, as well as in grey literature in the field of knowledge.Consequently, access to knowledge generated through other scientific dissemination media is left aside.A similar situation occurs with the language since main scientific data bases include

Figure 1 :
Figure 1: Number of publications by year Source: compiled from bibliometric analysis In Figure 1, the indicators show a growing interest on the topic since 2001, 2006 being one of the most productive years with a number of 36 published articles.In the following years of 2007 to 2009, the number of publications

Figure 2 :
Figure 2: Number of publications by journal Source: Compiled from bibliometric analysisIFIP Advances in Information and Communication Technology, is the top journal with 7 articles published.This publication compiles the disclosures made in the framework of the International Conference on Electronic Business (ICEB), where technology issues involving e-commerce are discussed, ranging from platforms and Web services, to knowledge models for e-commerce for both the environment and the company, as well as peculiarities of the different applications of this technology[118].The second journal, with 6 articles, is the Industrial Management and Data Systems, in which papers about the social, cultural, organizational and cognitive impacts of e-commerce technology and advances in organizations worldwide are published[120].The third journal with most publication is the Journal of Internet Commerce, with 6 articles, which "promotes greater access to high quality presentations at conferences and workshops on computer fields"[121].The fourth publication, is the Electronic Commerce Research and Applications Journal[57],[122] with 5 articles.This journal aims to create and disseminate knowledge about e-commerce, considering it is a multidisciplinary area that should be developed in cooperation with other existing fields, such as Information Systems and Technology; Marketing, Finance and/or Supply Chain Management; Strategy and Management; Public policy; Telecommunications and Computer Science; and Legal Studies.In fifth place is the Indian Journal of Science and Technology with 5 articles and the following four publications have 4 articles each: Advanced Materials Research; Advanced Science Letters; Journal of Small Business and Enterprise Development; and finally, Mediterranean Journal of Social Sciences.
with 5 articles.This journal aims to create and disseminate knowledge about e-commerce, considering it is a multidisciplinary area that should be developed in cooperation with other existing fields, such as Information Systems and Technology; Marketing, Finance and/or Supply Chain Management; Strategy and Management; Public policy; Telecommunications and Computer Science; and Legal Studies.In fifth place is the Indian Journal of Science and Technology with 5 articles and the following four publications have 4 articles each: Advanced Materials Research; Advanced Science Letters; Journal of Small Business and Enterprise Development; and finally, Mediterranean Journal of Social Sciences.

Figure 3 :
Figure 3: Cumulative percentage publications by journal Source: Compiled from bibliometric analysisRegarding the analysis of researchers with production in the field, Figure4displays the list of the ten researchers who have most productions in this subject area.MacGregor, R.C., who has 9 publications, appears on the top.Robert MacGregor is an associate professor in the School of Informatics and Computer Science at the University of Wollongong in Australia.His research expertise is in the area of information technology (IT) and electronic commerce (E-commerce) in small and medium sized enterprises (SMEs).He is the author of articles and conference publications examining the use and adoption of ICT in SMEs series.MacGregor is also the founding editor of the Australasian Journal of Information Systems and was president of the Australian Information Systems Conference in 1992[124].The following authors in the list are Vrazalic, L., with 8 publications; Govindaraju, R., Kartiwi, M. and Zhu, L., with 5 publications each; Kurnia, S., Scupola, A. and Thatcher, S.M.B., with 4 articles each; and the last two authors with 3 publications each are Al-Somali, S.A. and Chandra, D.R. (Figure4).

Figure 4 :
Figure 4: Authors with higher production Source: Compiled from bibliometric analysis

Figure 5 :
Figure 5: Cumulative percentage of publications by author Source: Compiled from bibliometric analysis

Figure 6 :
Figure 6: Productivity law by journals Source: Compiled from bibliometric analysis

Figure 7 :
Figure 7: Productivity law by author Source: Compiled from bibliometric analysis

Figure 8 :
Figure 8: Number of citations by author Source: Compiled from bibliometric analysis

Figure 9 :
Figure 9: Number of citations by journal Source: Compiled from bibliometric analysis

Figure 10 :
Figure 10: Number of citations by year Source: Compiled from bibliometric analysis

Figure 11 :
Figure 11: Keyword dynamics Source: Compiled from bibliometric analysis

Figure 13 :
Figure 13: Thematic evolution timeline Source: Compiled from bibliometric analysis

Table 3 :
Structure indicators Source: Own elaboration, done with cytoscape software

Table 4 :
Adoption factors identified through paper with keyword adoption

Table 4
displays a series of factors that, according to the authors mentioned, enable and encourage e-commerce adoption.With the intention of higlighting recurrent e-commerce adoption factors, Figure