1. Department of Otolaryngology–Head and Neck Surgery Stanford University School of Medicine Stanford California U.S.A.
2. Department of Otorhinolaryngology and Mayo Clinic Children's Center Mayo Clinic Rochester Minnesota U.S.A.
3. University of California Davis Blaisdell Medical Library Davis California U.S.A.
4. Howard University College of Medicine Washington, DC U.S.A
5. Lucile Packard Children's Hospital Stanford Aerodigestive and Airway Reconstruction Center Stanford California U.S.A.