1. Birth rates for U.S. teenagers reach historic lows for all age and ethnic groups. NCHS Data Brief, no 89;Hamilton,2012
2. Teenagers in the United States: Sexual activity, contraceptive use, and childbearing, National Survey of Family Growth 2006–2008. National Center for Health Statistics;Abma;Vital Health Stat,2010
3. Use of contraception in the United States: 1982–2008;Mosher;Vital Health Stat,2010
4. United Nations Demographic Yearbook 2008, Table 10
5. Sexually transmitted diseases among American youth: incidence and prevalence estimates, 2000;Weinstock;Perspect Sex Reprod Health,2004