Thermolabile methylenetetrahydrofolate reductase and factor V Leiden in the risk of deep-vein thrombosis - Kluijtmans,L.A.; den Heijer,M.; Reitsma,P.H.; Heil,S.G.; Blom,H.J.; Rosendaal,F.R. (Thromb Haemost, 1998)