1. Atkinson, R. C. and Shiffrin, R. M. (1968) ‘Human memory: a proposed system and its component processes’, in Spence, K. W. and Spence, J. T. (eds), Advances in the Psychology of Learning and Motivation: Research and Theory, New York: Academic Press, vol. 2, 89–195.
2. Biesheuvel, S. (1943) African Intelligence, Johannesburg: South African Institute for Race Relations.
3. Biesheuvel, S. (1972) ‘An examination of Jensen’s theory concerning educability, heritability and population differences’, Psychologia Africana, 14, 87–94.
4. Research Bulletin 74-16;JB Carroll,1974
5. Carroll, J. B. (1980) Individual Difference Relations in Psychometric and Experimental Cognitive Tasks, Report 163, L. L. Thurstone Psychometric Laboratory, Chapel Hill, N.C.: University of North Carolina.