1. University Clinical Centre of Serbia, Clinic for Otorhinolaryngology and Maxillofacial Surgery, Belgrade, Serbia
2. University Clinical Centre of Serbia, Clinic for Otorhinolaryngology and Maxillofacial Surgery, Belgrade, Serbia + University of Belgrade, Faculty of Medicine, Department of Otorhinolaryngology with Maxillofacial Surgery, Belgrade, Serbia
3. University of Belgrade, Faculty of Medicine, Institute of Pathology, Belgrade, Serbia