Activated Clotting Time, Anticoagulation, Use of Heparin, and Thrombin Activation during Extra-corporeal Circulation: Changes under Aprotinin Therapy - Feindt, P; Volkmer, I; Seyfert, U; Huwer, H; Kalweit, G; Gams, E (The Thoracic and Cardiovascular Surgeon, 1993)