M. D. Muneeb and M. A. Naushad Baig, “Postoperative Pain after Gallbladder Retrieval from Umbilical and Epigastric Ports in Laparoscopic Cholecystectomy: A Randomized Controlled Trial”, J Dow Univ Health Sci, vol. 13, no. 3, pp. 138–142, Dec. 2019.