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.
Balk EM, Zucker DR, Engels EA, Wong JB, Williams JW Jr, Lau J.Balk EM, et al.J Gen Intern Med. 2001 Oct;16(10):701-11. doi: 10.1111/j.1525-1497.2001.00429.x.J Gen Intern Med. 2001.PMID: 11679039Free PMC article.
Balk EM, Lau J, Goudas LC, Jordan HS, Kupelnick B, Kim LU, Karas RH.Balk EM, et al.Ann Intern Med. 2003 Oct 21;139(8):670-82. doi: 10.7326/0003-4819-139-8-200310210-00011.Ann Intern Med. 2003.PMID: 14568856Review.