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.
Stern RK, Hagan H, Lelutiu-Weinberger C, Des Jarlais D, Scheinmann R, Strauss S, Pouget ER, Flom P.Stern RK, et al.BMC Med Res Methodol. 2008 Sep 14;8:62. doi: 10.1186/1471-2288-8-62.BMC Med Res Methodol. 2008.PMID: 18789163Free PMC article.Review.