1. Division of Gastroenterology, Department of Internal Medicine, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, South Korea;
2. Division of Gastroenterology, Department of Internal Medicine, Jeonbuk National University Medical School and Research Institute of Clinical Medicine, Jeonbuk National University-Biomedical Research Institute, Jeonbuk National University Hospital, Jeonju, South Korea;
3. Division of Biliopancreatology, Department of Internal Medicine, Wonkwang University Hospital, Wonkwang University School of Medicine, Iksan, Korea.