1. Department of Head and Neck Surgery and Oncology; the Netherlands Cancer Institute; Amsterdam the Netherlands
2. Department of Clinical Epidemiology, Biostatistics, and Bioinformatics; Amsterdam Medical Center; Amsterdam the Netherlands
3. Department of Otolaryngology-Head and Neck Surgery; Emory University; Atlanta Georgia U.S.A.
4. Department of Head and Neck Surgery and Oncology; St. James Hospital; Dublin Ireland
5. National Cancer Registry; Cork Ireland
6. Department of Oncology, Head and Neck Oncology Section; University Hospitals Leuven; Leuven Belgium
7. Department of ENT/Head and Neck Surgery; Lund University Hospital; Lund Sweden
8. Department of Head and Neck Surgery and Oncology; Johns Hopkins Medical Center; Baltimore Maryland U.S.A.
9. Institute of Phonetic Sciences; University of Amsterdam; Amsterdam the Netherlands
10. Department of Oral and Maxillofacial Surgery; Academic Medical Center; Amsterdam the Netherlands