Nurochim, E., Indarto, D., & Prayitno, A. (2016). Association betweenMaternal Age at Pregnancy, Socioeconomic Status, Physical Environment, Prenatal, Perinatal, Postnatal History, and the Risk of Mental Retardation. Journal of Maternal and Child Health, 1(2), 119–130. Retrieved from http://www.thejmch.com/index.php/thejmch/article/view/20