Johnson, S. (2014). How we got to now: Six innovations that made the modern world.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रJohnson, Steven. How We Got to Now: Six Innovations That Made the Modern World. 2014.
एमएलए (8वां संस्करण) प्रशस्ति पत्रJohnson, Steven. How We Got to Now: Six Innovations That Made the Modern World. 2014.
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