1. A proposed classification of pelvic endometriosis;Acosta;Obstet Gynecol,1973
2. An expanded classification of endometriosis;Buttram;Fertil Steril,1978
3. Suggested classification for endometriosis: relationship to infertility;Kistner;Fertil Steril,1977
4. Classification of endometriosis;American Fertility Society;Fertil Steril,1979
5. Calculation of survival rates for cancer;Berkson;Proc Mayo Clin,1959