Riccardi, M., A. Chialà, F. Iannone, V. Grattagliano, M. Covelli, and G. Lapadula. “Treatment of Digital Ulcers in Systemtic Sclerosis With Endothelin-1 Receptor Antagonist (bosentan)”. Reumatismo, vol. 59, no. 2, June 2007, pp. 135-9, doi:10.4081/reumatismo.2007.135.