Budi Yulhasfi Febrianto, Eddy Sutrisno , Frank Bietra Buchari , Utama Abdi Tarigan , Hidayat. “The Polymorphism Identification of Reduced Folate Carrier 1 (RFC1) in Patients of Non Syndromic Cleft Lip With or Without Cleft Palate in Sumatera Utara”. International Journal of Emerging Trends in Science and Technology, vol. 4, no. 10, Oct. 2017, pp. 6279-84, http://ijetst.in/index.php/ijetst/article/view/1238.