A comparison of subcutaneous low molecular weight heparin with warfarin sodium for prophylaxis against deep vein thrombosis after hip or knee implantation - Hull, R; Raskob, G; Pineo, G; Rosembloom, D; Evans, W; Mallory, T; Anquist, K; Smith, F; Hughes, G; Green, D; Elliott, C G; Panju, A; Brant, R (N Engl J Med, 1993)