1. Department of Pediatrics; Foundation IRCCS Policlinico San Matteo; University of Pavia; Italy
2. Department of Otorhinolaryngology; Foundation IRCCS Policlinico San Matteo; University of Pavia; Italy
3. Department of Pediatrics; Pneumo-pediatric Unit; University Hospital of Montpellier; France
4. Department of Pediatrics; San Paolo Hospital; University of Milan; Italy