Novel photoplethysmography cardiovascular assessments in patients with Raynaud's phenomenon and systemic sclerosis: a pilot study.
McKay ND, Griffiths B, Di Maria C, Hedley S, Murray A, Allen J. Novel photoplethysmography cardiovascular assessments in patients with Raynaud's phenomenon and systemic sclerosis: a pilot study. Rheumatology (Oxford). 2014 Oct; 53(10):1855-63.