1. 1. LeRoy EC, Black C, Fleischmajer R, Jablonska S, Krieg T, Medsger Jr T, et al. (1988) Scleroderma (systemic sclerosis): classification, subsets and pathogenesis. The Journal of rheumatology 15, 202-205.
2. 2. Minier T, Nagy Z, Bálint Z, Farkas H, Radics J, Kumánovics G, et al. (2010) Construct validity evaluation of the European Scleroderma Study Group activity index, and investigation of possible new disease activity markers in systemic sclerosis. Rheumatology (Oxford, England) 49, 1133-1145.
3. 3. Scussel-Lonzetti L, Joyal F, Raynauld JP, Roussin A, Rich E, Goulet JR, et al. (2002) Predicting mortality in systemic sclerosis: analysis of a cohort of 309 French Canadian patients with emphasis on features at diagnosis as predictive factors for survival. Medicine (Baltimore) 81, 154-167.
4. 4. Benrud-Larson LM, Haythornthwaite JA, Heinberg LJ, Boling C, Reed J, White B, et al. (2002) The impact of pain and symptoms of depression in scleroderma. Pain 95, 267-275.
5. 5. Nietert PJ, Mitchell HC, Bolster MB, Curran MY, Tilley BC, Silver RM (2005) Correlates of depression, including overall and gastrointestinal functional status, among patients with systemic sclerosis. The Journal of rheumatology 32, 51-57.