Full Text
The Full Text of this article is available as a PDF (32.0 KB).
letter . 1999 Jun;76(6):3349–3351. doi: 10.1016/S0006-3495(99)77488-6
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.