1. Digestive tract: biopsy instruments, procedures, and specimens;Waye,1981
2. Practical gastrointestinal endoscopy;Cotton,1982
3. Colonoscopy: diagnosis and treatment of colonic diseases;Shinya,1982
4. Gastrointestinal mucosal biopsy;Weinstein,1985
5. Flexible sigmoidoscopy;Katon,1985