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.
Croft A, Garner P.Croft A, et al. Among authors: garner p.BMJ. 1997 Nov 29;315(7120):1412-6. doi: 10.1136/bmj.315.7120.1412.BMJ. 1997.PMID: 9418088Free PMC article.Review.