S. Agarwal, A. Samad, K. Gupta, R. K. Singh, R. Srivastava, and A. M. Baseer, “Comparative efficacy of intravenous premedication of clonidine versus nalbuphine on intraoperative hemodynamic profile of patients during surgery under general anesthesia: a randomized study”, Int J Res Med Sci, vol. 7, no. 5, pp. 1733–1739, Apr. 2019.