Full text
PDF
letter . 1980 May 3;280(6223):1147–1148. doi: 10.1136/bmj.280.6223.1147-c
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.