1. ENT Department; Children's Hospital Srebrnjak; Zagreb Croatia
2. Department for Allergy and Pulmonology; Children's Hospital Srebrnjak; Zagreb Croatia
3. Faculty of Medicine; J.J. Strossmayer University of Osijek; Osijek Croatia
4. Department of Medicine; University Hospital Center Osijek; Osijek Croatia
5. Research Department; Children's Hospital Srebrnjak; Zagreb Croatia
6. ENT Department; University Hospital Center Sisters of Charity; Zagreb Croatia