1. Division of Gastroenterology, Department of Internal Medicine, Petz Aladár County and Teaching Hospital, Győr 9024, Hungary
2. Department of Gastroenterology, School of Medicine, Debrecen University, Debrecen 4032, Hungary
3. Department of Internal Medicine, Jósa András County Hospital, Nyíregyháza 4400, Hungary
4. Department of Internal Medicine, Municipal Hospital, Siófok 8600, Hungary
5. Department of Surgery, Semmelweis University, Budapest 1083, Hungary
6. Department of Internal Medicine, Jávorszky Ödön Municipal Hospital, Vác 2600, Hungary
7. Department of Internal Medicine, Kenézy Gyula County Hospital, Debrecen 4031, Hungary