1. University Clinic for Digestive Surgery - First Clinical Surgical Hospital, Clinical Center of Serbia, Department for Minimally Invasive Upper Digestive Surgery, Belgrade
2. Public Health Institute, Šabac
3. School of Medicine, Kosovska Mitrovica
4. School of Medicine, Institute for medical statistics, Belgrade + School of Medicine, Belgrade
5. University of Edinburgh, College of Medicine and Veterinary Medicine, Edinburgh Medical School: Biomedical Sciences, Edinburgh, United Kingdom
6. University Clinic for Digestive Surgery, First Clinical Surgical Hospital, Clinical Center of Serbia, Department for Minimally Invasive Upper Digestive Surgery, Belgrade + School of Medicine, Belgrade