Yadollahi, M. ., K. . Sadegi, and B. Shahraki Mojahed. “Effect of Spinal Anesthesia With Sufentanil on Length of Stages I and II of Labor in Singleton Pregnant Women: A Randomized Controlled Trial”. Universa Medicina, vol. 42, no. 1, Apr. 2023, pp. 94-100, doi:10.18051/UnivMed.2023.v42.94-100.