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 2650
4. Rigshospitalet, Copenhagen University Hospital; Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 7812; Copenhagen Denmark
5. Environmental Health Services; Fraser Health Authority; #218 - 610 Sixth Street New Westminster BC Canada V3L 3C2