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.
Costley PL, East CE.Costley PL, et al. Among authors: east ce.Cochrane Database Syst Rev. 2012 May 16;(5):CD009241. doi: 10.1002/14651858.CD009241.pub2.Cochrane Database Syst Rev. 2012.PMID: 22592738Updated.Review.