Stedman's Online Medical Dictionary. http://stedmansonline.com/content.aspx?id=mlrA0500000406&termtype=t. Accessed June 1, 2015.
Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.