1. Jefferson University School of Medicine, Gastroenterology and Hepatology, Philadelphia, Pennsylvania, United States
2. University of North Carolina, Gastroenterology and Hepatology, Chapel Hill, North Carolina, United States
3. Department of Gastroenterology, IRCCS Istituto Clinico Humanitas, Milan, Italy
4. University of Utah School of Medicine, Gastroenterology and Hepatology, Salt Lake City, Utah, United States