Umphress Jason L, Pecha R Erick, Urayama Shiro
Department of Internal Medicine, Division of Gastroenterology, University of California-Davis, Medical Center, 4150 V Street, Sacramento, CA 95817, USA.
Gastrointest Endosc. 2004 Dec;60(6):1021-4. doi: 10.1016/s0016-5107(04)02216-3.