Full text
PDFPage 1127-1130
. 1981 Apr 4;282(6270):1128–1130. doi: 10.1136/bmj.282.6270.1128
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.
