Sharma V K, Steinberg E N, Vasudeva R, Howden C W
Division of Digestive Diseases and Nutrition, Dorn Veterans Affairs Medical Center, University of South Carolina, Columbia 29203-6808, USA.
Gastrointest Endosc. 1997 Dec;46(6):541-3. doi: 10.1016/s0016-5107(97)70011-7.