1. Tubal sterilization—Review of methods;Wortman;Popul. Rep. (C) No. 7,1976
2. Relative risks and benefits of electric and nonelectric sterilization techniques;Hulka;J. Reprod. Med.,1978
3. A comparison of laparoscopic tubal occlusion by cautery, spring-loaded clip and tubal ring;Kessel,1976
4. An epidemiologic study of risk factors associated with pregnancy following female sterilization;Chi;Am. J. Obstet. Gynecol.,1980
5. Statistical methods for rates and proportions;Fleiss,1973