1. Baillargeon, R. (1993). The object concept revisited: New directions in the investigation of infants' physical knowledge. In C. E. Granrud (Ed.), Visual perception and cognition in infancy. Carnegie-Mellon Symposia on Cognition, Volume 23 (pp. 265-316). Hillsdale, NJ: Lawrence Erlbaum Associates, Inc.
2. Ball, W. A. (1973, April). The perception of causality in the infant. Paper presented at the Society for Research in Child Development, Philadelphia, PA.
3. Bornstein, M. H. (1985). Habituation of attention as a measure of visual information processing in human infants: Summary, systematization, and synthesis. In G. Gottlieb & N. A. Krasnegor (Eds.), Measurement of audition and vision in the first year of life (pp. 253-300). Norwood, NJ: Ablex.
4. Brazelton, T. B., Koslowski, B. & Main, M. (1974). The origins of reciprocity: The early mother-infant interaction. In M. Lewis & L. A. Rosenblum (Eds.), The effects of the infant on its caregiver (pp. 49-76). New York: Wiley.
5. Butterworth, G. & Grover, L. (1988). The origins of referential communication in human infancy. In L. Weiskrantz (Ed.), Thought without language (pp. 5-24). Oxford: Clarendon.