1. National Center for Voice and SpeechUniversity of Utah Salt Lake City Utah U.S.A.
2. Department of Communication Sciences and DisordersUniversity of Iowa Iowa City Iowa U.S.A.
3. Department of Otorhinolaryngology–Head and Neck SurgeryDivision of PhoniatricsUniversity Hospital Basel Basel Switzerland
4. Clinical Center for Voice CareDepartment of Otolaryngology–Head and Neck Surgery, University of Texas Southwestern Medical Center Dallas Texas U.S.A.