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.
Hirji KF, Fagerland MW.Hirji KF, et al. Among authors: fagerland mw.BMC Med Res Methodol. 2011 May 12;11:66. doi: 10.1186/1471-2288-11-66.BMC Med Res Methodol. 2011.PMID: 21569392Free PMC article.
Fagerland MW.Fagerland MW.BMC Med Res Methodol. 2012 Jun 14;12:78. doi: 10.1186/1471-2288-12-78.BMC Med Res Methodol. 2012.PMID: 22697476Free PMC article.