1. Department of Statistics Graduate School of Chung‐Ang University Seoul Republic of Korea
2. Medical Library Soonchunhyang University Bucheon Hospital Bucheon Korea
3. Division of Gastroenterology and Hepatology Department of Internal Medicine Soonchunhyang University School of Medicine Bucheon Hospital Bucheon Korea
4. Division of Gastroenterology and Hepatology Department of Internal Medicine Soonchunhyang University School of Medicine Seoul Korea
5. Division of Gastroenterology and Hepatology Department of Internal Medicine Soonchunhyang University School of Medicine Cheonan Korea
6. Department of Internal Medicine University of Ulsan College of Medicine Gangneung Asan Hospital Gangneung‐si Korea