1. Department of Otorhinolaryngology, Head and Neck Surgery; Martin Luther University Halle-Wittenberg; Halle (Saale) Germany
2. Robert Bosch Society for Medical Research; Robert Bosch Hospital; Stuttgart Germany
3. Department of Otolaryngology - Head and Neck Surgery; Western University; London Canada
4. Department of Otorhinolaryngology, Head and Neck Surgery; Copenhagen University Hospital Rigshospitalet; Copenhagen Denmark
5. Cochrane ENT; Oxford UK
6. Department of Otolaryngology; St. Louis University; St Louis Missouri USA
7. Guy's Hospital; London UK
8. evidENT, Ear Institute; University College London; London UK
9. Julius Center for Health Sciences and Primary Care & Department of Otorhinolaryngology; University Medical Center Utrecht, Utrecht University; Utrecht Netherlands