1. Contraception;Mishell;N Engl J Med,1989
2. The noncontraceptive health benefits from oral contraceptive use;Ory;Fam Plann Perspect,1982
3. Contraceptive Technology, 17th ed;Hatcher,1998
4. Mishell DR Jr, Stenchever MA, Droegemueller W, Herbst AL. Comprehensive Gynecology, 3rd ed. St. Louis: Mosby-Year Book, Inc., 1997:405, 532–3.
5. Breast cancer and hormonal contraceptives;Lancet,1996