*2.1. Database and Search Strategy*

The data were retrieved in the middle of 2019 from the Web of Science (WoS) Core Collection. It was decided to choose WoS because WoS (1) allows to download a large number of papers and (2) provides necessary information for scientometrics analysis, such as authors' affiliations, authors' keywords, the title of papers, publication year, research areas, as well as the number of citations and download times for each paper [39,40].

The search strategy was described as follow:

