1. Hatcher RA, Trussell J, Nelson A, Cates W, Stewart F, Kowal D. Contraceptive technology 19th edition; 2008.
2. ACOG Practice Bulletin #59;Obstet Gynecol,2005
3. National Survey of Family Growth 2002, Centers for disease control and prevention.
4. Obstetrician–gynecologists and the intrauterine device: a survey of attitudes and practice;Stanwood;Obstet Gynecol,2002