1. Faculty of Medicine, Belgrade + Clinical Center “Zemun”, Department of Otorhonolaringology, Belgrade
2. Faculty of Medicine, Belgrade + Clinical Center Serbia, Institute of Otorhinolaryngology, Belgrade
3. Faculty of Medicine, Novi Sad + Clinical Center of Vojvodina, Novi Sad
4. Mother and Child Health Institute, Department of Otorhinolaryngology, Belgrade
5. Military Medical Academy, Clinic for Otorhinolaryngology, Belgrade