1. Detailed diagnoses and procedures for patients discharged from short-stay hospitals, United States, 1986. Vital and health statistics. Series 13, No. 95;National Center for Health Statistics,1988
2. Mortality from pulmonary embolism in the United States: 1962–1985;Lilienfeld;Chest,1990
3. International classification of disease;World Health Organization,1975
4. Statistical methods for rates and proportions;Fleiss,1973