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 affiliation for the eleventh author is incorrect. Ping Ma is affiliated with the Department of Statistics, University of Georgia, 101 Cedar St, Athens, GA 30602, USA.
View on publisher site
PDF (116.2 KB)
