1. Mayo Clinic, Rochester, MN
2. New York Medical Center, New York, NY
3. VA Greater Los Angeles Healthcare System-Sepulveda and University of California, Los Angeles, CA
4. Stanford University School of Medicine, Stanford, CA
5. University of North Carolina, Chapel Hill, NC
6. St. Joseph Memorial Hospital, Murphysboro, IL
7. Murfreesboro Medical Center, Murfreesboro, TN
8. University of Washington, Seattle, WA
9. National Jewish Medical and Research Center, Denver, CO
10. Rhode Island Hospital, Providence, RI
11. Toronto, Canada
12. Houston Sleep Center, Houston, TX