1. Lappegard T. New fertility trends in Norway. Trends in First Childbirth Max-Planck-Gesellschaft. 2000:2(3).
2. Early marriages, adolescent and young pregnancies, Report by the Secretariat. Sixty-fifth world health assembly A65/13, WHO, A65/13 Provisional agenda item 13.4. WHO. 2012.
3. U.S. Teenage Pregnancy Statistics: Overall Trends. Trends by Race and Ethnicity and State-by-State Information. New York: The Alan Guttmacher Institute; 2004.
4. Body Size and Intelligence in 6year-olds: Are Offspring of Teenage Mothers at Risk?;Cornelius;Maternal and Child Health Journal,2008
5. Losing ground early: Protection, risk and change in poor children's cognitive performance;Ayoub;Early Childhood Research Quarterly,2009