Maharjan, S., and S. Shrestha. “Intraperitoneal and Periportal Injection of Bupivacaine for Pain After Laparoscopic Cholecystectomy”. Kathmandu University Medical Journal, vol. 7, no. 1, Apr. 2009, pp. 50-53, doi:10.3126/kumj.v7i1.1765.