1Robinett, Betty wallaee. 1978.Teaching English to speakers of other language: Substance and Technique University of Minnesota Press and Mc Graw- Hill International Book Company.
2CoMer, SP.1967. Thesignificance of learner' s errost. IRAL, Vol. V/4.
3Ellis, R. 1992. Second Language Acquisition and Language Pedagogy. Avon: Multillngual Matters.
4Finocchiaro, Mary. 1964. English as a Second Language:from Theory to Practice. Regents Publishing Company, In C.
5Leech, Geoffrey N., 1993, Principles of Pragmatic, London, Longman.
6Sapir, Edward.1921. Language: An Introduction to the study of speech. New York: Harcourt, Brace & CO.
7Selinger, L. Interlanguage. 1972. International Review of Applied Linguistics 10,209 - 30.