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.
Pignone M, Fowler-Brown A, Pletcher M, Tice JA.Pignone M, et al.Rockville (MD): Agency for Healthcare Research and Quality (US); 2003 Dec.Rockville (MD): Agency for Healthcare Research and Quality (US); 2003 Dec.PMID: 20722118Free Books & Documents.Review.