1. Division of Otolaryngology, Head and Neck Surgery, Department of Surgery, Faculty of medicine, Dalhousie University, Halifax, Nova Scotia, Canada
2. Collegium Helveticum, ETH/University of Zurich, Zurich, Switzerland
3. Department of Head and Neck Surgery, University Hospital Aintree, Liverpool, Merseyside, UK
4. Department of Head and Neck Surgery, York Teaching Hospital NHS Trust, UK