An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Schwartz BS, Lee BK, Lee GS, Stewart WF, Lee SS, Hwang KY, Ahn KD, Kim YB, Bolla KI, Simon D, Parsons PJ, Todd AC.Schwartz BS, et al. Among authors: ahn kd.Am J Epidemiol. 2001 Mar 1;153(5):453-64. doi: 10.1093/aje/153.5.453.Am J Epidemiol. 2001.PMID: 11226977
Schwartz BS, Lee BK, Stewart W, Ahn KD, Kelsey K, Bressler J.Schwartz BS, et al. Among authors: ahn kd.Arch Environ Health. 1997 Mar-Apr;52(2):97-103. doi: 10.1080/00039899709602871.Arch Environ Health. 1997.PMID: 9124882