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.
Allen PA, Smith AF, Vires-Collins H, Sperry S.Allen PA, et al.Psychol Aging. 1998 Jun;13(2):218-29. doi: 10.1037//0882-7974.13.2.218.Psychol Aging. 1998.PMID: 9640583