Norback, C. T., & Norback, P. G. (1979). The must words: The 6000 most important words for a successful and profitable vocabulary. McGraw-Hill.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNorback, Craig T., और Peter G. Norback. The Must Words: The 6000 Most Important Words for a Successful and Profitable Vocabulary. New York: McGraw-Hill, 1979.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNorback, Craig T., और Peter G. Norback. The Must Words: The 6000 Most Important Words for a Successful and Profitable Vocabulary. McGraw-Hill, 1979.
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