1. National Health Insurance Fund of Serbia, Belgrade, Serbia
2. University Clinical Centre of Serbia, Clinic for Digestive Surgery, Department for HBP Surgery, Belgrade, Serbia + University of Belgrade, Faculty of Medicine, Department for Surgery with Anesthesiology, Belgrade, Serbia
3. University of Belgrade, Faculty of Medicine, Department for Surgery with Anesthesiology, Belgrade, Serbia + Bežanijska Kosa University Hospital Medical Center, Department for HBP Surgery, Belgrade, Serbia
4. Bežanijska Kosa University Hospital Medical Center, Department for HBP Surgery, Belgrade, Serbia