1. Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear Harvard Medical School Boston Massachusetts USA
2. Department of Otolaryngology – Head and Neck Surgery University of Michigan Ann Arbor Michigan USA
3. Department of Otolaryngology – Head and Neck Surgery Methodist Estabrook Cancer Center Omaha Nebraska USA
4. Department of Otolaryngology – Head and Neck Surgery University of Toronto Toronto Ontario Canada