Figure 2.
Citation analysis of the countries or regions. The size of nodes is based on total citations. The thickness of lines is based on the times they cited each other. USA, United States of America.
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.