Virdi, S., Aditi, and S. Kaur. “Variation of Pregnancy-Associated Plasma Protein-A: A Level in the First Trimester of Pregnancy and Its Clinical Outcome”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol. 15, no. 10, Sept. 2026, pp. 3925-30, doi:10.18203/2320-1770.ijrcog20263426.