Chung, H.H., Park, J.K., Lee, K.H., Lee, J.K. and Lee, K.T. 2022. The rate of endoscopic observation of the major duodenal papilla can be increased by simple guideline. International Journal of Advances in Medicine. 9, 3 (Feb. 2022), 266–272. DOI:https://doi.org/10.18203/2349-3933.ijam20220375.