Response of the Activated Partial Thromboplastin Time (APTT) to Heparin Is Influenced by Coagulometers - Besselaar, A M H P van den; Meeuwisse-Braun, J; Strebus, A; Mansfeld, H Schaefer-van; Witteveen, E; Meer, F J M van der (Thrombosis and Haemostasis, 1995)