Full text
PDFPage 1600
letter . 1977 Jun 18;1(6076):1600. doi: 10.1136/bmj.1.6076.1600-b
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.