FIGURE 4.
(A) Top 50 keywords with the strongest citation bursts. (B) Top 25 references with the strongest citation bursts.
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.