Biber, D. (1991). Variation across speech and writing. Cambridge University.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रBiber, Douglas. Variation Across Speech and Writing. Cambridge: Cambridge University, 1991.
एमएलए (9वां संस्करण) प्रशस्ति पत्रBiber, Douglas. Variation Across Speech and Writing. Cambridge University, 1991.
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