1. Ahlstroem, K. G.Transfer and cummunality: An experimental study of learning, Uppsala: Almqvist and Wiksells, 1961.
2. Amthauer, R.Intelligenzstruktur-Test. Göttingen: Hogrefe, 1963.
3. Bloom, B. S. Individual differences in school achievement: A vanishing point? Paper presented at the AERA Convention, 1971.
4. Boring, E. G. Communality in relation to proaction and retroaction.American Journal of Psychology, 1941,54, 280–283.
5. Bunderson, C. V.Transfer functions and learning curves: The use of ability constructs in the study of human learning. (Research Bulletin 64–62). Princeton, N. J.: Educational Testing Service, 1964.