1. Abney, S. 1987, The noun phrase in its sentential aspect. Ph.D. dissertation, Cambridge, MA: MIT.
2. Aksu, A. A. 1978, Aspect and modality in the child's acquisition of the Turkish past tense. Ph.D. dissertation, University of California at Berkeley.
3. How children talk about what happened;Antinucci;Journal of Child Language,1976
4. Language development. From two to three;Bloom,1991
5. A first language: The early stages;Brown,1973