Singh S, Pai S, Sahu B. Study of umbilical coiling index and perinatal outcome. Int J Reprod Contracept Obstet Gynecol [Internet]. 2020 Sep. 25 [cited 2025 Nov. 25];9(10):3977-82. Available from: https://www.ijrcog.org/index.php/ijrcog/article/view/9136