1. Learning in the Development of Infant Locomotion
2. Barker, R. G. (1968). Ecological psychology: Concepts and methods for studying the environment of human behavior. Stanford, CA: Stanford University Press.
3. Beck, J. (1972). Surface color perception. Ithaca, NY: Cornell University Press.
4. Boring, E. G. (1963). The physical dimensions of consciousness. New York: Dover. (Original work published 1933)