*2.1. Databases*

As in most research, the chances of covering a complete universe of study are small (the number of databases is very large). Therefore, three conditions should be complied with to choose the database. These are set out by Rueda et al. [26]: availability, relevance, and reliability of information.

Thus, the selection of databases was based on three criteria: (a) application of rigorous quality standards through Relative Quality Indexes, SJR (Scimago Journal Rank) for Scopus and JCR (InCites Journal Citation Report) for WoS (Web of Science); (b) extensive coverage over time compared to other databases; and (c) they allow for simultaneous downloading of a considerable number of references stored in detail as metadata. According to Harzing and Alakangas [27], the presence of these characteristics validates the information indexed in the database and are sufficient to justify its use.

### *2.2. Tracking Methodology*

To construct the data matrix with which to work, it is necessary to establish the search criteria of the bibliographic production. Firstly, the coverage time was determined; in this study, this was set as equal to or less than the year 2018, with the purpose of considering the information published in full years. Secondly, the scientific article published in journals was determined as the documentary unit of analysis. This choice was based on the consideration of six criteria: (1) speed within publication processes, (2) rigorous arbitration process, (3) visibility and impact at different levels (local, national, and international), (4) specific outline for presenting the information, (5) acceleration in the positioning of the authors within the scientific community, and (6) increase of the feedback [28,29]. The articles from conferences, books and chapters, editorials, notes, letters or errata contained in WoS or Scopus were excluded from the search. Finally, the keywords and search equation were determined for the advanced search (Table 1).


**Table 1.** Search strategy.

Source: own elaboration.
