1. Gastroenterology Department, Colentina Clinical Hospital, Carol Davila University of Medicine, 020125 Bucharest, Romania
2. Department of Gastroenterology, Royal Stoke University Hospital, Stoke-on-Trent ST4 6QG, UK
3. Digestive Endoscopy Unit, Fondazione Policlinico Universitario A. Gemelli, IRCCS, 00168 Rome, Italy