Ahmed, Raju, et al. “Comparative Study of Dexmedetomidine and Fentanyl As an Adjuvant to Epidural Bupivacaine for Post-Operative Pain Relief in Hepato-Biliary Pancreatic Surgery”. Anwer Khan Modern Medical College Journal, vol. 10, no. 2, Nov. 2019, pp. 143-9, doi:10.3329/akmmcj.v10i2.44127.