1. Gastroenterology and GI Endoscopy Unit, Academic Medical Center of Udine, Udine, Italy
2. Gastroenterology and GI Endoscopy Unit, Mater Olbia Hospital, Qatar Foundation Endowment & Gemelli Foundation, Olbia, Italy
3. Department for Digestive Endoscopy, Ospedale Isola Tiberina – Gemelli Isola, Rome, Italy
4. Department of Pathology, Academic Medical Center of Udine, Udine, Italy
5. GI Endoscopy Unit, University Clinic “Dr Dragisa Misovic - Dedinje”, Belgrade, Serbia
6. Clinic for Gastroenterohepatology, University Clinical Centre of Belgrade, Belgrade, Serbia