1. University of Florida, Gainesville, Florida
2. Clayton Sleep Institute, Maplewood, Missouri
3. Paoli Hospital Sleep Center, Paoli, Pennsylvania
4. Norton Clinical Research Group, Louisville, Kentucky
5. St. Luke's Hospital, Chesterfield, Missouri
6. Med One Sleep, Fayetteville, North Carolina
7. Sleep Disorders Center of Alabama, Birmingham, Alabama
8. The Center for Sleep and Wake Disorders, Chevy Chase, Maryland