Individual time within target range in patients treated with vitamin K antagonists: main determinant of quality of anticoagulation and predictor of clinical outcome. A retrospective study of 2300 consecutive patients with venous thromboembolism - Veeger, N J; Piersma-Wichers, M; Tijssen, J G; Hillege, H L; van der Meer, J (Br J Haematol, 2005)