Full Text
The Full Text of this article is available as a PDF (94.4 KB).
letter . 2002 May;61(5):472. doi: 10.1136/ard.61.5.472
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.