Fig. 2. Schematic representation of the shortlisting process (adaptation of the 2020 PRISMA guidelines for reviews).

The sequential reduction in the number of articles is shown in descending order. Since there are overlapping search fields in the different databases, a large proportion of the total number of papers were redundant, leading to the removal of duplicates. The authors read the article titles to determine which abstracts were appropriate for reading. The relevancy of the abstracts was used to locate candidate articles for full reading, with the exclusion criteria being applied to these candidates to arrive at a final selection of papers.