Nepal, M., R. Paudel, R. Poudel, and N. Gautam. “Analgesic Efficacy and Tolerability of Tramadol Versus Low Dose Tramadol-Paracetamol in Patients With Gastro Intestinal Surgery”. Journal of Universal College of Medical Sciences, vol. 7, no. 2, Dec. 2019, pp. 39-45, doi:10.3126/jucms.v7i2.27136.