Mondol, Mohammmad Shaddam Hoshain, et al. “The Effect of Oral Clonidine at Different Doses on Post-Operative Analgesic and Hemodynamic Status in Upper Abdominal Surgery”. Journal of Dhaka Medical College, vol. 28, no. 2, Jan. 2021, pp. 131-5, doi:10.3329/jdmc.v28i2.51147.