1. A brief history of endoscopy;Modlin,2000
2. History of the instruments for gastrointestinal endoscopy;Edmonson;Gastrointest Endosc,1991
3. Gastrointestinal endoscopy;Haubrich,1994
4. The development of the endoscope;Schuman,1997
5. Gastroscopy. The endoscopic study of gastric pathology;Schindler,1950