N. U. Ahmed, M. Hossain, A. Akhtaruzzaman, M. K. Mondol, and U. S. Khatun, “Addition of clonidine or fentanyl with bupivacaine for supraclavicular brachial plexus blocks in upper limb surgery - a randomized comparative study”, j Bangladesh Soc Anaesthesiologists, vol. 24, no. 1, pp. 3–7, Aug. 2014.