Dashti Khavidaki, G., Keykha, A., Beirami, F., Khoshfetrat, M. and Shirazian, F. 2018. The effect of using pre-operative ketamine injection on post-tonsillectomy pain intensity in children. Biomedical Research and Therapy. 5, 02 (Feb. 2018), 2013-2021. DOI:https://doi.org/10.15419/bmrat.v5i02.416.