1. Bridges, A., and J. Smith. 1984. Syntactic comprehension in Down’s syndrome children. British Journal of Psychology 75: 187–196.
2. Brown, R. 1973. A first language. Cambridge, MA: Harvard University Press.
3. Carrow-Woolfolk, E. 1985. Test for auditory comprehension of language (TACL-R). Ann Arbor, MI: Pro-Ed.
4. Dunn, D., and D. Dunn. 1997. Peabody picture vocabulary test, 3rd ed. Circle Pines, MN: American Guidance Service.
5. Fowler, A., R. Gelman, and L. Gleitman. 1994. The course of language learning in children with Down Syndrome: Longitudinal and language level comparisons with young normally developing children. In Constraints on language acquisition: Studies of atypical children, ed. H. Tager-Flusberg. Hillsdale, NY: Lawrence Erlbaum Associates.