Endoscopic retrogarde cholangiopancreatography and needle-knife sphincterotomy in patients with Billroth II gastrectomy: A comparative study of the forward-viewing endoscope and the side-viewing duodenoscope. - Kim,M.H.; Lee,S.K.; Lee,M.H.; Myung,S.J.; Yoo,B.M.; Seo,D.W.; Min,Y.I. (Endoscopy, 1997)