Preston, D. R., & Roger W. Shuy. (1988). Varieties of American English: Teacher's handbook. D.C.: U.S. Information Agency.
Chicago Style aipamenaPreston, Dennis R., và Roger W. Shuy. Varieties of American English: Teacher's Handbook. D.C.: U.S. Information Agency, 1988.
MLA aipamenaPreston, Dennis R., và Roger W. Shuy. Varieties of American English: Teacher's Handbook. D.C.: U.S. Information Agency, 1988.
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