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.
Helfand M; U.S. Preventive Services Task Force.Helfand M, et al.Ann Intern Med. 2004 Jan 20;140(2):128-41. doi: 10.7326/0003-4819-140-2-200401200-00015.Ann Intern Med. 2004.PMID: 14734337Free article.Review.
Helfand M, Crapo LM.Helfand M, et al.Ann Intern Med. 1990 Jun 1;112(11):840-9. doi: 10.7326/0003-4819-112-11-840.Ann Intern Med. 1990.PMID: 2111649Review.
Carney N, Chesnut RM, Maynard H, Mann NC, Patterson P, Helfand M.Carney N, et al. Among authors: helfand m.J Head Trauma Rehabil. 1999 Jun;14(3):277-307. doi: 10.1097/00001199-199906000-00008.J Head Trauma Rehabil. 1999.PMID: 10381980Review.