Varghese, S., G. Kour, K. Manchanda, and T. Dhar. “Abnormal Umbilical Artery Doppler in Third Trimester and Perinatal Outcome: A Retrospective Study”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol. 5, no. 7, Feb. 2017, pp. 2196-9, doi:10.18203/2320-1770.ijrcog20162092.