1. Ethinylestradiol and dl-norgestrel as a postcoital contraceptive;Yuzpe;Fertil Steril,1977
2. Anticoncepción poscoital: un recurso necesario. Editorial;Lete;Boletín de la Sociedad Española de Contracepción,1999
3. Presription drug products: certain combined oral contraceptives for use as emergency postcoital contraception;Fed Regist,1997
4. Little knowledge and limites practice: emergency contraceptive pills, the public and the obstetrician-gynecologists;Del Banco;Obstet Gynecol,1997
5. Should emergency contraception pills available without prescription?;Ellertson;J Am Med Women Assoc,1998