1. Kalter H. Five-decade international trends in the relation of perinatal mortality and congenital malformations: stillbirth and neonatal death compared. Int J Epidemiol 1991;20:173?179.
2. National Centre for Health Statistics. Vital and health statistics of the United States. Vol II. Mortality. Part A, section 3. Fetal Mortality. Hyattsville, Maryland: National Centre for Health Statistics, 1968?1988.
3. Department of Economic and Social Development, Statistical Division, 1991 Demographic Yearbook. United Nations/New York, New York: 1992.
4. Breslow NE, Day NE. Statistical methods in cancer research. Vol I. The analysis of case control studies. IARC Scientific Publications no. 32, Lyon, 1980.
5. Miettinen OS. Theoretical Epidemiology: principles of occurrence research in medicine. New York: Delmar Publishers Inc, 1985.