Extrinsic pathway inhibitor (EPI) released to the blood by heparin is a more powerful coagulation inhibitor than is recombinant EPI - Lindahl, A K; Abildgaard, U; Larsen, M L; Staalesen, R; Hammer, A KG; Sandset, P M; Norfang, O; Beck, T C (Thromb Res, 1991)