Full text
PDFPage 797
. 1980 Dec;44(4):797. doi: 10.1128/mr.44.4.797-797.1980
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.