Caldwell S H, Brantley K, Dent J, Keeley R C, Pruett T, Angle J F, Gaffey M, Waldron P
Division of Gastroenterology, Hepatology, and Nutrition, University of Virginia Health Sciences Center, Charlottesville 22908.
Ann Intern Med. 1994 Jul 1;121(1):34-6. doi: 10.7326/0003-4819-121-1-199407010-00006.