1. Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania U.S.A.
2. Drexel University College of Medicine Philadelphia Pennsylvania U.S.A.
3. Division of Otolaryngology Cleveland Clinic Cleveland Ohio U.S.A.
4. Department of Otorhinolaryngology – Head and Neck Surgery University of Pennsylvania Health System Philadelphia Pennsylvania U.S.A.
5. Department of Biostatistics, Epidemiology and Informatics University of Pennsylvania Philadelphia Pennsylvania U.S.A.
6. Health Science Libraries University of Pennsylvania Philadelphia Pennsylvania U.S.A.
7. Division of Otolaryngology Children's Hospital of Philadelphia Philadelphia Pennsylvania U.S.A.