4Hymes, D. Introduction: Toward Ethnographies of Communication. In Gumperz, J. J & Hymes, D. (eds), The Ethnog- raphy of Communication, Special Issue of American Anthropologist [ M ]. New York:Holt, Rinehart and Winston, 1964.
5Wardhaugh, R. An Introduction to Sociolinguistics (second edition) [ M ]. London:Blackwe11, 1992.