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.
The author co-citation network map (A) and co-authorship overlay map (B) generated by VOS viewer. Each node represents an author, and node size indicates the number of publications. The purple nodes represent the author appear earlier, whereas the red nodes reflect the recent occurrence.
