Full Text
The Full Text of this article is available as a PDF (20.2 KB).
letter . 2001 Sep;81(3):1823–1824. doi: 10.1016/S0006-3495(01)75832-8
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.