[1] Univ Zurich, Univ Hosp Zurich, Dept Rheumatol, Zurich, Switzerland
[2] Univ Bern, Bern Univ Hosp, Dept Rheumatol & Immunol, Inselspital, Bern, Switzerland
[3] Sandro Pertini Hosp, Interdisciplinary Reference Ctr Syst Sclerosis CRI, Rome, Italy
[4] Univ Florence, Dept Stat, Informat, Applicat, Florence, Italy
[5] Univ Calif Los Angeles, Los Angeles, CA USA
[6] Univ Washington, Seattle, WA USA
[7] Univ Florence, Florence, Italy
[8] Univ Hosp Tuebingen, Dept Internal Med Hematol Oncol Immunol & Rheumato, Tubingen, Germany
[9] Univ Zagreb, Univ Hosp Ctr Zagreb, Dept Internal Med, Div Clin Immunol & Rheumatol,Sch Med, Zagreb, Croatia
[10] Univ Brescia, Rheumatol & Clin Immunol Unit, ASST Spedali Civili Brescia, Brescia, Italy
[11] Bogomolets Natl Med Univ, Kiev, Ukraine
[12] Carol Davila Univ Med & Pharm, Cantacuzino Hosp, Ion Cantacuzino Hosp, Bucharest, Romania
[13] Padova Univ Hosp, Rheumatol Unit, Padua, Italy
[14] Univ Med Ctr, Utrecht, Netherlands
[15] Oslo Univ Hosp, Dept Rheumatol, Oslo, Norway