“Fentanyl and Clonidine With Local Anaesthetics in Supraclavicular Brachial Plexus Block for Post Operative Analgesia : A Comparative Study”. Asian Journal of Pharmaceutical and Health Sciences, vol. 6, no. 3, Sept. 2016, pp. 1514-21, https://ajphs.com/index.php/ajphs/article/view/387.