1. Clinical Center of Serbia, Belgrade, Serbia;
2. Faculty of Medicine, University of Belgrade, Belgrade, Serbia;
3. Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria;
4. Department of Otorhinolaryngology, Head and Neck Surgery, Landeskrankenhaus Mistelbach, Mistelbach, Austria;
5. Department of Ophthalmology, Medical University of Vienna, Vienna, Austria;
6. Department of Otorhinolaryngology, Faculty of Medicine, Military Medical Academy, University of Defence, Belgrade, Serbia;
7. Institute of Head and Neck Diseases, Evangelical Hospital Vienna, Vienna, Austria