1. ENT Clinic, University of Tor Vergata, Roma, viale Oxford 81, 00133, Italy
2. ENT Department, Policlinico S.M. alle Scotte Siena, viale Bracci n.16, 53100, Italy
3. Department of Otolaryngology Head and Neck Surgery Osmangazi University, Faculty of Medicine, Büyükdere Mahallesi, Meşelik Yerleşkesi, 26040 Odunpazarı/Eskişehir, Turchia
4. Servicio de Endoscopia Respiratoria, Hospital de Pediatría Prof. Dr. Juan P. Garrahan, Combate de los Pozos 1881, C1245AAM CABA, Buenos Aires, Argentina