1. Parental underinvestment;Ballweg;Population Research and Policy Review,1992
2. Mothers, babies, and disease in later life;Barker,1994
3. Birth order, family size, and intelligence;Belmont;Science,1973
4. Birth order, family size and school failure;Belmont;Developmental Medicine and Child Neurology,1976
5. Regular skewness of birth order distribution;Berglin,1980