1. Medical Faculty, University of Nis; Department of Internal Medicine; Zorana Djindjica 81 Nis Serbia 18000
2. Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 7812, Rigshospitalet, Copenhagen University Hospital; The Cochrane Hepato-Biliary Group; Blegdamsvej 9 Copenhagen Denmark DK-2100
3. Copenhagen University Hospital Hvidovre; Gastrounit, Medical Division; Kettegaards Alle Hvidovre Denmark
4. Rigshospitalet, Copenhagen University Hospital; Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 7812; Copenhagen Denmark
5. Ospedali Riuniti Villa Sofia-Cervello; U.O. di Medicina 2; Via Trabucco 180 Palermo Italy I-90146
6. Medical Faculty, University of Nis; Institute of Anatomy; Boulevard Dr Zorana Djindjica 81 Nis Serbia 18000