1. Euromedic General Hospital, Bulevar umetnosti 29, 11070 Belgrade, Serbia
2. School of Medicine Foca, University East Sarajevo, Studentska 5, 73300 Foca, Bosnia and Herzegovina
3. Department for Minimally Invasive Upper Digestive Surgery, Hospital for Digestive Surgery, Clinical Center of Serbia, Dr Koste Todorovica Street 6, 11000 Belgrade, Serbia
4. School of Medicine, University of Belgrade, Dr Subotica Street 8, 11000 Belgrade, Serbia
5. Department of Anesthesiology and Resuscitation, Hospital for Digestive Surgery, Clinical Center of Serbia, Dr Koste Todorovica Street 6, 11000 Belgrade, Serbia
6. University Hospital Medical Center Bezanijska Kosa, Dr Zorza Matea Street, 11000 Belgrade, Serbia