Frequency of pregnancy-related venous thromboembolism in anticoagulant factor-deficient women: implications for prophylaxis - Friederich, PW; Sanson, BJ; Simioni, P; Zanardi, S; Huisman, MV; Kindt, I; Prandoni, P; Buller, HR; Girolami, A; Prins, MH (Ann Intern Med, 1996)