Ekaputri, Prasila. “Transvaginal Ultrasound Assessment of Cervical Length in Threatened Preterm Labor”. Indonesian Journal of Obstetrics and Gynecology 36, no. 2 (December 8, 2020): 81–84. Accessed March 17, 2026. https://www.inajog.com/index.php/journal/article/view/1481.