1. Department of Clinical and Experimental Medicine, Division of Rheumatology, University of Florence, AOU Careggi, Florence, Italy
2. Department of Internal Medicine and Rheumatology, Justus-Liebig-University Giessen, Giessen
3. Department of Rheumatology, Clinical Immunology, Osteology and Physical Medicine Kerckhoff-Klinik, Bad Nauheim, Germany
4. Department of Rheumatology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
5. University of Michigan Scleroderma Program, Department of Medicine, University of Michigan, Ann Arbor, MI, USA