1. Barlow, D. H., & Hersen, M. (1984).Single case experimental designs: Strategies for studying behavior change (2nd ed.). Elmsford, New York: Pergamon Press.
2. Bates, E. (1979).The emergence of symbols: Cognition and communication in infancy. New York: Academic Press.
3. Beisler, J. M., & Tsai, L. Y. (1983). A pragmatic approach to increase expressive language in young autistic children.Journal of Autism and Developmental Disorders, 13, 287?303.
4. Bloom, L., & Lahey, M. (1978).Language development and language disorders. New York: Wiley.
5. Carr, E. G., Binkoff, J. A., Kologinsky, E., & Eddy, E. (1978). Acquisition of sign language by autistic children. I. Expressive labelling.Journal of Applied Behavior Analysis, 11, 489?501.