Frequency of pregnancy-related venous thromboembolism in anticoagulant factor-deficient women: implications for prophylaxis - Friederich, P; Sanson, B; Simioni, P; Zanaidi, S; Huisman, M; Kindt, I; Prandoni, P; Büller, H; Girolami, A; Prins, M (Annals Int Med, 1996)