The American College of Rheumatology 1990 criteria for the classification of vasculitis. Introduction - Hunder,G.G.; Arend,W.P.; Bloch,D.A.; Calabrese,L.H.; Fauci,A.S.; Fries,J.F.; Leavitt,R.Y.; Lie,J.T.; Lightfoot,R.WJ.; Masi,A.T. (Arthritis Rheum, 1990)