1. Department of Internal Medicine, University of Michigan Scleroderma Program, Ann Arbor
2. Centre for Rheumatology and Connective Tissue Disease, Royal Free Hospital, London, United Kingdom
3. Division of Rheumatology, University of Pennsylvania, Philadelphia
4. Department of Dermatology, University of Cologne, Cologne, Germany
5. Actelion Pharmaceuticals Ltd, Allschwil, Switzerland
6. Department of Medicine, Division of Rheumatology, University of Western Ontario, London, Ontario, Canada
7. Department of Experimental and Clinical Medicine, Division of Rheumatology, AOUC, University of Florence, Florence, Italy
8. Division of Rheumatology, UCLA, Los Angeles