Vitayaburananont, P., and P. Nuchpramool. “Assess Level of Post-Operative Pain in Adult Patients Who Underwent Elective Surgery Using Pre-Printed Postoperative Pain Order in Vajira Hospital”. Vajira Medical Journal : Journal of Urban Medicine, vol. 64, no. 2, Apr. 2020, pp. 125-32, doi:10.14456/vmj.2020.12.