Figure 1.
The overall papers included in the review, with points of exclusion for both phases. The blue band represents the search engine round evaluations, and the green band represents the snowballing round evaluations.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.