PUN, A.; DHUNGANA, A.; PARIYAR, J.; UPADHYAY, H. P. Effectiveness of Fentanyl in Facilitating Cannulation of Ampulla of Vater during Endoscopic Retrograde Cholangiopancreatography. Journal of Nepal Health Research Council, v. 18, n. 4, p. 753-757, 22 Jan. 2021.