1. Clinic of Gastroenterology, Clinical Centre of Serbia; Department of Hepatology; Koste Todorovica 2 Belgrade Serbia 11000
2. Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 3344, Rigshospitalet, Copenhagen University Hospital; The Cochrane Hepato-Biliary Group; Blegdamsvej 9 Copenhagen Denmark DK-2100
3. Clinical Hospital Centre Rijeka; Department of Gastroenterology; Kresimirova 42 Rijeka Croatia 51000
4. Clinic of Gastroenterology, Clinical Centre of Serbia; Belgrade Serbia 11000
5. Medical Faculty, University of Nis; Department of Internal Medicine; Zorana Djindjica 81 Nis Serbia 18000