Shafiq, Hamid, and Asifa Majeed. “Vitamin D Deficiency and Parathormone Levels in Punjabi Pakistani Population”. Pakistan Journal of Physiology 15, no. 2 (June 30, 2019): 7-10. Accessed March 28, 2020. https://pjp.pps.org.pk/index.php/PJP/article/view/1049.