4)Joseph Carl Yarze, John Varga, David Stampfl, et al : Esophageal Function in Systemic Sclerosis : A Prospective Evaluation of Motility and Acid Reflux in 36 Patients. Am J Gastroentel 1993 ; 88 : 870-876
5) Carol M. Black : Scleroderma-clinical aspects. J In ternal Medicine 1993 ; 234 : 115-118