1. Division of Gastroenterology-Hepatology; Department of Internal Medicine; Maastricht University Medical Center; Maastricht The Netherlands
2. Wingate Institute of Neurogastroenterology; Centre for Digestive Diseases; Blizard Institute; Barts and the London School of Medicine and Dentistry; Queen Mary University of London; London UK
3. Department of Gastroenterology; University Hospitals of North Midlands; Stoke on Trent Staffordshire UK