The content is available as a PDF (48.0 KB).
. 1999 Mar;96(3):505. doi: 10.1046/j.1365-2567.1999.00757.x
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.