• A case-control study of breast cancer and hormonal contraception in Costa Rica 

      Rosero Bixby, Luis; Grimaldo Vásquez, Carmen; Rovira, Elizabeth; Lee, Nancy C.; Oberle, Mark W.; Watley, Anne S. (1987)
      By 1981, 11% of married women in Costa Rica ages 20-49 years had used depot-medroxyprogesterone acetate (DMPA) and 58% had used oral contraceptives (OCs). Since 1977, the Costa Rican Ministry of Health has maintained a ...