Kumar, R., K. Kunwar, A. Kumar, and N. Agrawal. “To Determine the Prevalence of Vitamin D Among Pregnant Women and Its Impact on Feto- Maternal Outcome”. International Journal of Health and Clinical Research, vol. 3, no. 12(S), Dec. 2020, pp. 65-70, https://www.ijhcr.com/index.php/ijhcr/article/view/630.