The influence of anticoagulant treatment on the probability of function in femoropopliteal vein bypass surgery: Analysis of a clinical series (1970 to 1985) and interim evaluation of a controlled clinical trial - Kretschmer, G; Wenzl, E; Piza, F; Polterauer, P; Ehringer, H; Minar, E; Schemper, M (Surgery, 1987)