1. Department of Otorhinolaryngology, Faculty of Medicine, Military Medical Academy, University of Defence, Belgrade, Serbia
2. Faculty of Medicine, University of Novi Sad, Serbia
3. Clinical Centre of Vojvodina, Clinic for Otorhinolaryngology and Head and Neck Surgery, Novi Sad, Serbia
4. Faculty of Medicine, Institute for Pathology, Military Medical Academy, University of Defence, Belgrade, Serbia