TY - JOUR AN - 60 AU - Lawrenson,R. AU - Farmer,R. TI - Venous thromboembolism and combined oral contraceptives: does the type of progestogen make a difference? JO - Contraception PY - 2000 VL - 62(2, suppl) SP - 21S-28S; discussion 37S–38S M2 - 21S DO - 10.1016/S0010-7824(00)00147-5 ER -