1

Number of authors

Number of authors who contributed to the study.

2

International

Whether the authors are from several countries or not, or whether they are part of a research group.

3

Same organization

Whether or not the authors belong to the same organization.

4

Country of the first author

The country of the institution to which the first author is affiliated. In the case of mentioning several institutions, the first affiliation was considered.

5

Country of the other authors

The countries of the institutions to which the other authors are affiliated. In the case of mentioning several institutions, the first affiliation was considered.