Full text
PDF
letter . 1963 May 25;1(5342):1413–1414. doi: 10.1136/bmj.1.5342.1413-a
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.
