Vandervoort J, Weiss E J, Somnay K, Tham T C, Wong R C, Carr-Locke D L
Division of Gastroenterology, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Gastrointest Endosc. 1996 Dec;44(6):739-41. doi: 10.1016/s0016-5107(96)70065-2.