1. Faculty of Medicine, Belgrade + Clinical Centre of Serbia, Clinic for Gastroenterology and Hepatology, Belgrade
2. Clinical Centre of Serbia, Clinic for Gastroenterology and Hepatology, Belgrade
3. Military Medical Academy, Clinic for Gastroenterology, Belgrade + University of Defence, Faculty of Medicine of the Military Medical Academy, Belgrade
4. Faculty of Medicine, University of Belgrade, Belgrade + Clinical Centre of Serbia, Institute for Hematology, Belgrade
5. Faculty of Medicine, University of Belgrade, Belgrade + First Surgical University Hospital Clinic, Belgrade