The risk of recurrent venous thromboembolism after discontinuing anticoagulation in patients with acute proximal deep vein thrombosis or pulmonary embolism. A prospective cohort study in 1626 patients - Prandoni, P; Noventa, F; Ghirarduzzi, A; Pengo, V; Bernardi, E; Pesavento, R (Haematologica, 2007)