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