Affiliation: | Y‐H Chung, Division of Gastroenterology, Department of Internal Medicine, University of Ulsan, College of Medicine, Asan Medical Centre, Seoul, Korea;N H Park, Division of Gastroenterology, Department of Internal Medicine, University of Ulsan College of Medicine, Ulsan University Hospital, Ulsan;I H Song, Division of Gastroenterology, Department of Internal Medicine, Dankook University College of Medicine, Cheonan, Korea |