1. Johns Hopkins University School of Public Health Baltimore, MD, Consultants in Epidemiology and Occupational Health, Inc (CEOH) Washington, DC
2. Johns Hopkins University School of Public Health Baltimore, MD, Consultants in Epidemiology and Occupational Health, Inc (CEOH) Washington, DC, Georgetown University School of Medicine, Department of Pediatrics Washington, DC
3. Consultants in Epidemiology and Occupational Health, Inc (CEOH) Washington, DC
4. Craigavon Area Hospital Group Trust Craigavon, Ireland
5. Department of Radiology, Mayo Clinic, Rochester, MN
6. Department of Neurology Mayo Clinic, Rochester, MN