1. Department of Otorhinolaryngology-Head and Neck Surgery; General Hospital of Volos; Volos
2. First Department of Pediatrics; Pediatric Pulmonology Unit; Sleep Disorders Laboratory, University of Athens School of Medicine and Aghia Sophia Children's Hospital; Athens
3. Department of Otorhinolaryngology-Head and Neck Surgery; General Hospital of Chania; Chania
4. Department of Otorhinolaryngology-Head and Neck Surgery; University of Thessaly School of Medicine and Larissa University Hospital; Larissa; Greece