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.
Burke LE, Dunbar-Jacob JM, Hill MN.Burke LE, et al.Ann Behav Med. 1997 Summer;19(3):239-63. doi: 10.1007/BF02892289.Ann Behav Med. 1997.PMID: 9603699Review.