Downey, D. B. (2001), "Number of siblings and intellectual development: The resource dilution explanation", American Psychologist, 56 (6–7): 497–504, doi:10.1037/0003-066X.56.6-7.497, PMID11413873.
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Falbo, Toni (1978), "Sibling Tutoring and Other Explanations for Intelligence Discontinuities of Only and Last Borns", Journal of Population, 1 (4): 349–363, doi:10.1007/BF00972557, JSTOR27507586, S2CID143544441.
Downey, D. B. (2001), "Number of siblings and intellectual development: The resource dilution explanation", American Psychologist, 56 (6–7): 497–504, doi:10.1037/0003-066X.56.6-7.497, PMID11413873.
Falbo, Toni (1978), "Sibling Tutoring and Other Explanations for Intelligence Discontinuities of Only and Last Borns", Journal of Population, 1 (4): 349–363, doi:10.1007/BF00972557, JSTOR27507586, S2CID143544441.