1. Department of Otorhinolaryngology – Head and Neck Surgery University of Pennsylvania Philadelphia Pennsylvania USA
2. Rush Medical College Rush University Medical Center Chicago Illinois USA
3. Department of Otorhinolaryngology – Head and Neck Surgery University of California Irvine Irvine California USA
4. Department of Otorhinolaryngology–Head and Neck Surgery Rush University Medical Center Chicago Illinois USA
5. Department of Neurosurgery University of Pennsylvania Philadelphia Pennsylvania USA
6. Department of Neurosurgery Children's Hospital of Philadelphia Philadelphia Pennsylvania USA