1. Departments of Otolaryngology of the Texas Children's Hospital; Baylor College of Medicine; Houston Texas U.S.A
2. Aiken ENT; Aiken South Carolina U.S.A
3. Louisiana State University Health Sciences Center Shreveport; Shreveport Louisiana U.S.A
4. University of North Carolina; Chapel Hill North Carolina U.S.A
5. University of Pennsylvania; Philadelphia Pennsylvania U.S.A