TRAN, T. N., NGUYEN, H. T., LE, D. T., & LE, T. H. (2016). PREVALENCE OF VITAMIN D DEFICIENCY AMONG PRIMARY SCHOOL CHILDREN IN 2012. Vietnam Journal of Nutrition & Food, 12(1), 47-52. https://tapchidinhduongthucpham.org.vn/index.php/jfns/article/view/568