1. Department of Internal Medicine Gastroenterology and Endoscopy Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
2. Digestive Endoscopy Istituto Auxologico Italiano Milan Italy
3. Gastroenterology and Endoscopy Unit, Area Chirurgia Specialistica Santa Chiara Hospital Trento Italy
4. Outpatient Department, Casa di Cura Villa Montallegro Genoa Italy