Cengiz, P., Gokcinar, D., Karabeyoglu, I., Topcu, H., Cicek, G. S., Gogus, N. Intraoperative low-dose ketamine infusion reduces acute postoperative pain following total knee replacement surgery: a prospective, randomized double-blind placebo-controlled trial. J Coll Physicians Surg Pak 2014; 5: 299-303