Hengcharoen, S., and S. Chaithongwongwatthana. “Awareness of Emergency Contraception in Adolescent Mothers”. Thai Journal of Obstetrics and Gynaecology, vol. 17, no. 3, May 2012, pp. 175-80, https://he02.tci-thaijo.org/index.php/tjog/article/view/1622.