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.
Ritter M, Laule-Kilian K, Klima T, Christ A, Christ M, Perruchoud A, Mueller C.Ritter M, et al.Swiss Med Wkly. 2006 May 13;136(19-20):311-7. doi: 10.4414/smw.2006.11321.Swiss Med Wkly. 2006.PMID: 16741854Free article.