Sanghvi, K. S., V. A. Shah, and K. D. Patel. “Comparative Study of Bupivacaine Alone and Bupivacaine Along With Buprenorphine in Axillary Brachial Plexus Block: A Prospective, Randomized, Single Blind Study”. International Journal of Basic & Clinical Pharmacology, vol. 2, no. 5, Feb. 2017, pp. 640-4, https://www.ijbcp.com/index.php/ijbcp/article/view/1333.