Rao, B. D., and K. C. Prakash. “Comparative Study of Intrathecal Bupivacaine 0.5% With Bupivacaine 0.5% and Buprenorphine Low Dose for Postoperative Analgesia in Lower Abdominal Surgeries”. International Surgery Journal, vol. 3, no. 1, Dec. 2016, pp. 253-7, doi:10.18203/2349-2902.isj20160237.