00371nam a22001457a 4500020001500000082001600015100002000031245004100051250001200092260003900104300001300143654002100156700002000177700002800197  a0632027061  a616.33bCOT  aCotton, Peter B  aPractical gastrointestinal endoscopy  a3rd ed.  aLondonbBlackwell Scientificc1990  a1-289 p.  aGastroenterology  aCotton, Peter B  aWilliams, Christopher B