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.
Cockerham RE, Margolis FL, Munger SD.Cockerham RE, et al. Among authors: margolis fl.BMC Res Notes. 2009 Mar 2;2:31. doi: 10.1186/1756-0500-2-31.BMC Res Notes. 2009.PMID: 19284705Free PMC article.