Yeasmeen, Sabina, et al. “Use of Labetalol and Glyceryl Trinitrate for Induced Hypotension in Spine Surgery- A Comparative Study”. Journal of the Bangladesh Society of Anaesthesiologists, vol. 22, no. 2, Mar. 2014, pp. 48-53, doi:10.3329/jbsa.v22i2.18141.