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.
Tolley K, Oliver N, Miranda E, Migliaccio-Walle K, Bozkaya D, Li Q.Tolley K, et al.J Med Econ. 2010;13(3):559-70. doi: 10.3111/13696998.2010.516203.J Med Econ. 2010.PMID: 20812793Free article.