Figure 2.
(A) The cooperation network visualizations map of countries and regions based on CiteSpace; (B) The average annual publication year map of countries and regions based on VOSviewer.
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.