Full text
PDFPage 138
letter . 1994 Feb;102(2):138. doi: 10.1289/ehp.94102138b
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.
