Polit, D. F. & Falbo, T. (1987). «Only children and personality development: A quantitative review». Journal of Marriage and the family49 (2): 309-325. JSTOR352302. doi:10.2307/352302.
Polit, D. F. & Falbo, T. (1988). «The intellectual achievement of only children». Journal of Biosocial Science20 (3): 275-285. PMID3063715. doi:10.1017/S0021932000006611.
Polit, D. F. & Falbo, T. (1987). «Only children and personality development: A quantitative review». Journal of Marriage and the family49 (2): 309-325. JSTOR352302. doi:10.2307/352302.
Polit, D. F. & Falbo, T. (1988). «The intellectual achievement of only children». Journal of Biosocial Science20 (3): 275-285. PMID3063715. doi:10.1017/S0021932000006611.