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.
Moffat DA, Hardy DG.Moffat DA, et al. Among authors: hardy dg.J R Soc Med. 1989 Jun;82(6):329-32. doi: 10.1177/014107688908200606.J R Soc Med. 1989.PMID: 2509698Free PMC article.