1. Hamilton, B. E., & Ventura, S. J. (2010). Births: Preliminary data for 2009. National vital statistics reports. Hyattsville, MD: National Center for Health Statistics.
2. Hamilton, B. E., & Ventura, S. J. (2007). Births: Preliminary data for 2006. National vital statistics reports. Hyattsville, MD: National Center for Health Statistics.
3. Singh, S., & Darroch, J. E. (2000). Adolescent pregnancy and childbearing: Levels and trends in developed countries. Family Planning Perspectives, 32, 14–23.
4. Vital signs: Teen pregnancy—United States, 1991–2009. Morbidity and Mortality Weekly Report, 60, 414–420.
5. Kohler, P. K., Manhart, L. E., & Lafferty, W. E. (2008). Abstinence-only and comprehensive sex education and the initiation of sexual activity and teen pregnancy. Journal of Adolescent Health, 42, 344–351.