Levine M, Hirsh J, Arnold A, Gent M, Levine M, Arnold A, Bramwell V, Pritchard KI, Stewart D, Warr D, Goodwin P, Samosh M, Falanga A. Double-blind randomised trial of very-low-dose warfarin for prevention of thromboembolism in stage IV breast cancer. The Lancet. 1994 Apr;343(8902):886–9. doi: 10.1016/s0140-6736(94)90008-6.