1. Thromboembolic complications of pregnancy;Bolan;Clin Obstet Gynecol,1983
2. Venous thromboembolic disease in pregnancy;Sipes;Seminars in Perinatology,1990
3. Deep venous thrombosis and pulmonary embolism in pregnancy;Rutherford;Obstet Gynecol Clin North Am,1991
4. Statistics and Information Department, Minister's Secretariat, Ministry of Health and Welfare, Japan Vital Statistics of Japan 1988, 1989, 1990, 1991, 1992 Statistics and Information Department, Minister's Secretariat, Ministry of Health and Welfare