“Treatment of Digital Ulcers in Systemtic Sclerosis With Endothelin-1 Receptor Antagonist (bosentan)”. Reumatismo 59, no. 2 (June 30, 2007): 135–139. Accessed April 25, 2025. https://www.reumatismo.org/reuma/article/view/reumatismo.2007.135.