1. Fitts, P., & Posner, M. I. (1967). Human performance. Belmont, CA: Brooks/Cole
2. The ability to learn.
3. Binet, A., & Simon, T. (1905). New methods for the diagnosis of the intellectual level of subnormals. L'Année Psychologique, 11, 191–244. Translated by Elizabeth S. Kite and reprinted in J. J. Jenkins & D. G. Paterson (Eds.), Studies of individual differences: The search for intelligence (pp. 90–96). New York: Appleton-Century-Crofts
4. Zeaman, D., & House, B. J. (1967). The relation of IQ and learning. In R. M. Gagné (Ed.), Learning and individual differences (pp. 192–212). Columbus, OH: Charles Merrill
5. Knowledge and processing speed as determinants of associative learning.