RT Journal Article SR Electronic T1 Current concepts of Prinzmetal’s variant form of angina pectoris JF Cleveland Clinic Journal of Medicine JO Cleve Clin J Med FD Cleveland Clinic SP 131 OP 141 VO 43 IS 3 A1 Heupler, Frederick A. YR 1976 UL http://www.ccjm.org/content/43/3/131.abstract AB