Figure 3: Distribution of papers based on publication date
Source : authors
Figure 4 shows the geographical distribution of the articles identified after the exclusion of the duplicates, while Figure 5 shows the geographical distribution of the included papers. In the case of the identified papers (Figure 4), the highest frequency of publications comes from the United States and England. However, after the conclusion of Stage 2.1 (identifying, selecting and the inclusion of papers), the geographic dispersion of the publications has changed. The concentration of papers originating from Europe increased (20), followed by Asia (4). South America and Oceania have one paper each.