1. Department of Otorhinolaryngology, Faculty of Medicine of the Military Medical Academy, University of Defence, Belgrade, Serbia
2. Institute for Pathology, Faculty of Medicine of the Military Medical Academy, University of Defence, Belgrade, Serbia
3. Department of Otorhinolaryngology, Military Medical Academy, Belgrade, Serbia
4. Hospital “Dr. Žutić”, Belgrade, Serbia
5. ENT University Clinic, University Campus “St. Mother Theresa”, Skopje, Republic of North Macedonia