Kaufman, J. (2013). The first 20 hours: How to learn anything ... fast. Portfolio/Penguin.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रKaufman, Josh. The First 20 Hours: How to Learn Anything ... Fast. New York: Portfolio/Penguin, 2013.
एमएलए (8वां संस्करण) प्रशस्ति पत्रKaufman, Josh. The First 20 Hours: How to Learn Anything ... Fast. Portfolio/Penguin, 2013.
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