Full text
PDFPage 642
. 1992 Feb 11;20(3):642. doi: 10.1093/nar/20.3.642
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.