Table 2.
Characteristics of research methods
Items in black-type face represent those of the published manuscript. Items in red-type face represent those obtained through contacting the authors of the pertinent manuscript
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.