Ergin, Rahime Nida, and Murat Yayla. “Second Trimester Uterine Artery Pulsatility Index and Chorionicity in Twins”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology 3, no. 3 (January 4, 2017): 497–500. Accessed October 4, 2025. https://www.ijrcog.org/index.php/ijrcog/article/view/980.