1. 14 and Younger,2003
2. No Easy Answers;Kirby,1997
3. Trends in Sexual Activity and Contraceptive Use among Teens;Terry,2000
4. National Campaign to Prevent Teen Pregnancy. With one voice 2002: America’s adults and teens sound off about teen pregnancy. Available from: www.teenpregnancy.org/resources/data/pdf/teenwant.pdf. Accessed September 2003.
5. A Statistical Portrait of Adolescent Sex, Contraception, and Childbearing;Moore,1998