Abdelshafy, A., K. I. Abdullah, S. Ashoush, and H. E. Hosni. “The Role of Sildenafil Citrate in the Treatment of Fetal Growth Restriction: A Randomized Controlled Trial”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol. 8, no. 5, Apr. 2019, pp. 1840-6, doi:10.18203/2320-1770.ijrcog20191929.