1. Clinical-Hospital Center “Bežanijska Kosa” , Belgrade , Serbia
2. Department of Internal Medicine, Faculty of Medical Sciences , University of Kragujevac , Kragujevac , Serbia
3. Clinical Centre Kragujevac, Clinic of Gastroenterohepatology , Kragujevac , Serbia
4. Clinical Centre Kragujevac, Clinic of Cardiology , Kragujevac , Serbia