1. Callahan, T. L., & Caughey, A. B. (2007). Contraception and sterilization. In N. A. Duffy & K. Horvath (Eds.), Obstetrics & gynecology (pp. 248–266). Baltimore: Lippincott Williams & Wilkins.
2. Jones, J., Mosher, W. D., & Daniels, K. (2012). Current contraceptive use in the United States, 2006–2010, and change in patterns of use since 1995. National Center for Health Statistics (pp. 2012–1250). Hyattsville: US Department of Health and Human Services, Centers for Disease Control and Prevention. DHHS publication.
3. Medline Plus. (2010). Birth control. Retrieved 31 Oct 2016, from
http://www.nlm.nih.gov/medlineplus/birthcontrol.html
4. Rowlands, S. (2009). New technologies in contraception. BJOG: An International Journal of Obstetrics & Gynaecology, 116(2), 230–239.
5. Wong, D., Hockenberry, M., Wilson, D., Perry, S., & Lowdermilk, D. (2006). Maternal child nursing care (3rd ed.). St. Louis: Mosby Elsevier.