G. lakhe, K. M. Adhikari, K. Khatri, A. Maharjan, A. Bajracharya, and H. Khanal, “Prevention of Shivering during Spinal Anesthesia: Comparison between Tramadol, Ketamine and Ondansetron”, J Nepal Med Assoc, vol. 56, no. 208, pp. 395–400, Dec. 2017.