1. British natltOna1 _orut/zrn-%No 14;Committec, Joint Formulary,1987
2. Oral contraceptives and cardiovascular disease. Part 1;By, Stadel;N EttglJ Med,1981
3. Female hormones and vascular disease-an epidemiological overview. British 7ournal of Family Planning;Vessey, M.P.,1980
4. Coagulation cffects of oral contraception;Bonnar, J.;Am. Obstet Gynecol; A comparison of the efl.tl,1987
5. Oral contraceptives and surgery: reduced antithrombin and antifactor Xa levels without postoperative thrombosis in low-risk patients;Gallus AS, Chooi CC, Konetschnik F, Goodall KT;Thromb Res,1984