Mao, Mao, Zhaohui Wang, Caijuan Li, Nan Wang, Shanwu Feng, Shiqin Xu, Xiaofeng Shen, and Xian Wang. “Effectiveness of A Single Dose of Epidural Morphine for Postpartum Perineal Pain: A Randomized Controlled Trial”. Science Insights 2017, no. 5 (June 20, 2017): 1–6. Accessed March 29, 2024. https://bonoi.org/index.php/si/article/view/148.