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.
Schiff M, Becker TM, Masuk M, van Asselt-King L, Wheeler CM, Altobelli KK, North CQ, Nahmias AJ.Schiff M, et al. Among authors: becker tm.Am J Epidemiol. 2000 Oct 15;152(8):716-26. doi: 10.1093/aje/152.8.716.Am J Epidemiol. 2000.PMID: 11052549
Becker TM, Wheeler CM, McGough NS, Parmenter CA, Jordan SW, Stidley CA, McPherson RS, Dorin MH.Becker TM, et al.JAMA. 1994 Apr 20;271(15):1181-8.JAMA. 1994.PMID: 8151876