1. Kost K, Henshaw S, Carlin L. US teenage pregnancies, births and abortions: national and state trends and trends by race and ethnicity, 2010. Washington, DC: Guttmacher Institute; 2010.
2. Santelli J, Sandfort T, Orr M. Transnational comparisons of adolescent contraceptive use: what can we learn from these comparisons? Arch Pediatr Adolesc Med. 2008;162:92–4.
3. Finer LB, Henshaw SK. Disparities in rates of unintended pregnancy in the United States, 1994 and 2001. Perspect Sex Reprod Health. 2006;38:90–6.
4. Hamilton BE, Martin JA, Ventura SJ. Births: preliminary data for 2007. National Center for Health Statistics. Natl Vital Stat Rep. 2009;57(12):1–23.
5. Martin JA, Hamilton BE, Sutton PD, et al. Births: final data for 2007. National Center for Health Statistics. Natl Vital Stat Rep. 2010;58(24):1–86.