1. Chicago, Illinois, San Antonio, Texas, Philadelphia, Pennsylvania, Denver, Colorado, and Miami, Florida
2. Department of Otolaryngology, Northwestern University Medical School, Chicago
3. Department of Otolaryngology, University of Texas Medical Center, San Antonio
4. Department of Otolaryngology, Medical College of Philadelphia, Ahanemann University, Philadelphia
5. Department of Otolaryngology, University of Colorado School of Medicine, Denver
6. Departments of Medicine and Department of Biometrics and Preventive Medicine, University of Colorado Health Sciences Center
7. Department of Otolaryngology, University of Miami School of Medicine, Miami