Effect of a subanesthetic dose of intravenous ketamine and/or local anesthetic infiltration on hemodynamic responses to skull-pin placement: a prospective, placebo-controlled, randomized, double-blind study - Agarwal, A; Sinha, P K; Pandey, C M; Gaur, A; Pandey, C K; Kaushik, S (J Neurosurg Anesthesiol, 2001)