Sandeep Dubey; Rukhsana Najeeb; Arshid Ahmad Sofi. A Comparative Study of Efficacy of Clonidine and Dexmedetomidine As An Adjuvant to Ropivacaine in Ultrasound Guided Supraclavicular Brachial Plexus Block Vis-À-Vis Onset of Surgical Anaesthesia and Duration of Effect in Upper Limb Surgeries. jmbas 2020, 8, 513-520.