1. Department of Gastroenterology and Hepatology, University of Kansas School of Medicine, Kansas City, Kansas, United States
2. Department of Internal Medicine, University of Kansas School of Medicine, Kansas City, Kansas, United States
3. Department of Gastroenterology and Hepatology, Veteran Affairs Medical Center, Kansas City, Missouri, United States
4. Department of Gastroenterology and Hepatology, Penn State Hershey Medical Center, Hershey, Pennsylvania, United States
5. Department of Gastroenterology and Hepatology, The Royal Free Hospital and University College London, London, United Kingdom
6. Department of Gastroenterology and Hepatology, Nuovo Regina Margherita Hospital, Digestive Endoscopy Unit, Rome, Italy
7. Department of Gastroenterology and Hepatology, Humanitas Clinical and Research Center and Humanitas University, Digestive Endoscopy Unit, Division of Gastroenterology, Rozzano, Italy