1. Cleveland Clinic Cleveland Ohio
2. University of California Los Angeles
3. Banner University Medical CenterUniversity of Arizona Phoenix
4. Intermountain Medical Center, Murray, Utah and University of Utah School of Medicine Salt Lake City
5. University of Pennsylvania Health System Philadelphia
6. University of Chicago Chicago Illinois
7. University of Michigan Scleroderma Program Ann Arbor
8. Santa Barbara Pulmonary Associates Santa Barbara California
9. Institution of Clinical PhysiologyNational Research Council Pisa Italy
10. Federico II University Naples Italy
11. University Hospital Salerno Italy
12. University of Illinois College of Medicine at Chicago
13. University of Washington School of Medicine Seattle