Citazione APA

Retherford, R. D., & Sewell, W. H. (1991). Birth order and intelligence. Reprints of the East West Population Institute 271.

Stile di citazione Chicago

Retherford, Robert D., e William Hamilton Sewell. "Birth Order and Intelligence." Reprints of the East West Population Institute 271 1991.

Citazione MLA

Retherford, Robert D., e William Hamilton Sewell. "Birth Order and Intelligence." Reprints of the East West Population Institute 271 1991.

Attenzione: Queste citazioni potrebbero non essere precise al 100%.