Low Levels of Protein S Activity in Factor V Depleted Plasma Used in APC Resistance Test - Samama, M. S.; Gouin-Thibault, I.; Trossaert, M.; Dreden, P. Van; Combot, C.; Amiral, J.; Horellou, M. H.; Conard, J. (Thrombosis and Haemostasis, 1998)