Banerjee, A.; Bhattacharya, P.; Wankhede, R. G.; Rudra, A.; Sengupta, S.; Sen, S. Study the Impact of Ketamine, Clonidine and Combination of Ketamine-Clonidine on Cardiovascular System During Pre and Postoperatively: A Double Blind, Placebo Controlled Study. Int. J. Heal. Clin. Res. 2020, 3, 109-118.