1. Gastrointestinal Unit Department of Medicine, Surgery and Dentistry Scuola Medica Salernitana University of Salerno Salerno Italy
2. Pio Albergo Trivulzio Hospital Milano Italy
3. S. Giovanni Addolorata Hospital Roma Italy
4. Division of Gastroenterology B AOUI Verona Verona Italy
5. UNC Center for Functional GI & Motility Disorders University of North Carolina at Chapel Hill Chapel Hill NC USA