Usma Jabeen, Zaid Muneer, and Mohammad Khairat, “Comparison of intraoperative and postoperative analgesic efficacy of Fentanyl versus Dexmedetomidine as an adjuvant to epidural Ropivacaine in patients undergoing major abdominal surgeries: an observational study”, Int. J. Heal. Clin. Res., vol. 4, no. 2, pp. 283–287, Jan. 2021.