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.
Kernick DP, Goadsby PJ; Royal College of General Practitioners; British Association for the Study of Headache.Kernick DP, et al.Cephalalgia. 2011 Jan;31(1):106-11. doi: 10.1177/0333102410378046. Epub 2010 Jul 29.Cephalalgia. 2011.PMID: 20670994