1. Department of Head and Neck Surgery and Oncology, Nederlands Kanker Instituut - Antoni van Leeuwenhoek Ziekenhuis, Amsterdam, The Netherlands
2. Department of Otorhinolaryngology/Head and Neck Surgery, Universitair Medisch Centrum Groningen, Groningen, The Netherlands
3. Institute of Phonetic Sciences, University of Amsterdan, Amsterdan, The Netherlands
4. Department of Maxillofacial Surgery, Academic Medical Center, University of Amsterdan, Amsterdan, The Netherlands