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.
Blair RJ.Blair RJ.Philos Trans R Soc Lond B Biol Sci. 2008 Aug 12;363(1503):2557-65. doi: 10.1098/rstb.2008.0027.Philos Trans R Soc Lond B Biol Sci. 2008.PMID: 18434283Free PMC article.Review.