## 4 Discussion and Limitations
### Limitations  
This research faced several limitations that could have had an impact on the obtained results, most of them related to the process of dataset extraction.  
The main limitation is the inclusion of only one database, namely WoS, into the analysis. The argument for taking into consideration only one database was based on the prestige of WoS, which offers a variety of sources, according to papers in the academic community that also had been investigated before the decision was made. The indexes that are very popular, such as Social Sciences Citations Index (SSCI) or Science Citation Index Expanded (SCIE), are part of the WoS database, providing a robust analysis of the citations. At the same time, the Keywords Plus [30] variable is offered by WoS and identifies the terms derived from the references in the document, highlighting the scope of the analysis, a feature that is not offered by other databases. In order to further support the choice for a single database for the bibliometric analysis, a fact that should also be stated is that using multiple databases would have interfered with the analysis conducted in terms of the number of citations, as it would have been hard to decide which database to use for these analyses because various situations might arise, such as papers missing from one or another database or duplicated in multiple databases. To support this point of view, in Table 5, we included the number of citations recorded for the five most cited papers included in the dataset, according to each database.  
Furthermore, it should be mentioned that, as access to the WoS database is based on a paid subscription, the resulting dataset might be different depending on the level of the subscription. As stated at the beginning of the paper, in this case, we had access to all 10 indexes offered by WoS.  
The exclusion of any other language apart from English stands as a constraint for the research, limiting the temporal coverage of papers. The decision to include only English language papers was intentional, in order to have a relevant n-grams and themes analysis. At the same time, we were restricted to English due to the lack of proficiency in any other languages. In our case, only three papers among those initially extracted were published in a language other than English, showing that the decision to exclude papers in other languages would not affect the outcome in a decisive manner.  
The software tool that was used for the bibliometric approach, the Biblioshiny library from the R programming language, is a popular tool used, together with VOSViewer for analysis of specific datasets extracted from databases [41]. For example, Biblioshiny is able to analyze Scopus, Dimensions, Cochrane Library, WoS, Lens, and PubMed, while VOSViewer is able to work with Lens, Scopus, WoS, PubMed and Dimensions [101].  
The inclusion of only the documents that were marked as \"Article\" in the WoS database [102] represents another limitation, but the step was mandatory in order to obtain a representative comparison among papers from the number of citations and content perspectives.  
Lastly, somewhat different results might be obtained if the steps provided in the paper are slightly different when selecting the dataset.  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Paper**} & \multicolumn{3}{c}{**Number of Citations**} \\ \cline{2-3}  & **ISI Web of Science (Database** & **Scopus** \\  & **Used in This Study)** & **Scopus** \\ \hline [PERSON] et al. [44] & 614 & 714 \\ \hline [PERSON] et al. [55] & 241 & - \\ \hline [PERSON] et al. [56] & 225 & - \\ \hline [PERSON] [61] & 193 & 238 \\ \hline [PERSON] et al. [62] & 171 & - \\ \hline \hline \end{tabular}
\end{table}
Table 5: Example of citations for top-five most cited papers included in the dataset.