1. Oncology Institute of Vojvodina, Sremska Kamenica + University of Novi Sad, Faculty of Medicine, Novi Sad
2. Military Medical Academy, Department of Gastroenterology, Belgrade
3. Clinical Hospital Center “Bežanijska Kosa”, Clinic of Oncology, Belgrade
4. Institute of Oncology and Radiology of Serbia, Department of Medical Oncology, Belgrade
5. Oncomed-System, Belgrade