1. Johns Hopkins School of Medicine, Baltimore, Maryland, USA
2. Johns Hopkins Cochlear Center for Hearing and Public Health, Baltimore, Maryland, USA
3. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
4. Johns Hopkins School of Nursing, Baltimore, Maryland, USA
5. Welch Medical Library, Johns Hopkins University, Baltimore, Maryland, USA
6. Department of Otolaryngology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA