1. Unit of Otorhinolaryngology, Department of Surgery, University Hospital, University of Cagliari.
2. Unit of Plastic Surgery & Microsurgery, Department of Surgery, University Hospital, University of Cagliari.
3. Unit of Otorhinolaryngology, Department of Surgery, University Hospital, University of Cagliari; I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia.
4. NHS Lanarkshire Glasgow.
5. Unit of Pathology, Department of Surgery, University Hospital, University of Cagliari.