Ward, P. D. (2005). Life as we do not know it: The NASA search for (and synthesis of) alien life. Viking.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रWard, Peter D. Life as We Do Not Know It: The NASA Search for (and Synthesis of) Alien Life. New York: Viking, 2005.
एमएलए (8वां संस्करण) प्रशस्ति पत्रWard, Peter D. Life as We Do Not Know It: The NASA Search for (and Synthesis of) Alien Life. Viking, 2005.
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