1. W. Stern, Über Psychologie der Individuellen Differenzen (Leipzig, 1900 ).
2. Introduced by W. Stern in his Die Differentielle Psychologie (Leipzig, 1911).
3. J. S. Mill, Autobiography 1969 edn (Oxford University Press) pp. 232–3.
4. R. J. Herrnstein, IQ in the Meritocracy ( London: Allen Lane, 1973 ).
5. A. R. Jensen, ‘How Much Can We Boost IQ and ScholasticAchievement?’, Harvard Educational Review, vol. 39 (1969) pp. 1–123.