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