Rationale and design of a clinical trial of a low-molecular-weight heparin in preventing clinically important venous thromboembolism in medical patients: the prospective evaluation of dalteparin efficacy for prevention of venous thromboembolism in immobilized patients trial (the PREVENT study). - Vaitkus,P.T.; Leizorovicz,A.; Goldhaber,S.Z. (Vasc Med, 2002)