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.
Sheikh A, Walker S.Sheikh A, et al. Among authors: walker s.BMJ. 2002 Dec 7;325(7376):1337. doi: 10.1136/bmj.325.7376.1337.BMJ. 2002.PMID: 12468484Free PMC article.Review.No abstract available.
Sheikh A, Walker S.Sheikh A, et al. Among authors: walker s.BMJ. 2005 Aug 6;331(7512):330. doi: 10.1136/bmj.331.7512.330.BMJ. 2005.PMID: 16081446Free PMC article.Review.No abstract available.