Results of a multicenter study assessing the status of standardization of a recombinant thromboplastin for the control of oral anticoagulant therapy - Tripodi, A; Chantarangkul, V; Braga, M; Poller, L; ten Cate, J W; van den Besselaar, A MPH; Mannucci, P M (Thromb Haemost, 1994)