Bahgat, Nagwan Ahmed. “Relation Between Maternal Vitamin D Level and in Vitro-Fertilization Laboratory Outcome in Normal Responding Patients 35 Years Old or Less”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology 11, no. 11 (October 28, 2022): 2943–2947. Accessed December 4, 2025. https://www.ijrcog.org/index.php/ijrcog/article/view/12256.