B. P. Thangappah, R., U. Sampson, A. Azad, R. Arumugam, S. Anand, and P. Karunakaran. “A Study to Evaluate Serum 25-Hydroxy Vitamin D3 and Calcium Levels in Maternal and Cord Blood and Their Effect on Pregnancy Outcome”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol. 8, no. 4, Mar. 2019, pp. 1575-82, doi:10.18203/2320-1770.ijrcog20191221.