Bell, I.P.1985: Communication and language in mental handicap. 5. Don't teach - intervene. Mental Handicap13, 17-19.
2.
Bloom, L. and Lahey, M.1978: Language development and language disorders. New York: John Wiley.
3.
Crystal, D., Fletcher, P. and Garman,M.1976. The grammatical analysis of language disability. London: Edward Arnold.
4.
Sigelman, C.K., Budd, E.C., Winer, J.L., Schoenrock, C.J. and Martin, P.W.1982: Evaluating alternative techniques of questioning mentally retarded persons. American Journal of Mental Deficiency86, 511-518.
