Serednicka K, Smyth AE, Black CM, Denton CP. Using a self-reported functional score to assess disease progression in systemic sclerosis. Rheumatology (Oxford), 2007 Jul;46(7):1107-10
Smyth AE, MacGregor AJ, Mukerjee D, Brough GM, Black CM, Denton CP. A cross-sectional comparison of three self-reported functional indices in scleroderma. Rheumatology (Oxford), 2003 Jun;42(6):732-8.
Herrick A, Rooney B, Finn J, Silman A. Lack of relationship between functional ability and skin score in patients with systemic sclerosis. J Rheumatol. 2001 Feb;28(2):292-5.