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.
Burch JA, Soares-Weiser K, St John DJ, Duffy S, Smith S, Kleijnen J, Westwood M.Burch JA, et al. Among authors: duffy s.J Med Screen. 2007;14(3):132-7. doi: 10.1258/096914107782066220.J Med Screen. 2007.PMID: 17925085Review.
Rodgers M, Griffin S, Paulden M, Slack R, Duffy S, Ingram JR, Woolacott N, Sculpher M.Rodgers M, et al. Among authors: duffy s.Pharmacoeconomics. 2010;28(5):351-62. doi: 10.2165/11532160-000000000-00000.Pharmacoeconomics. 2010.PMID: 20131924Review.