Guthke, K. S. Are we alone?: The idea of extraterrestrial intelligence in philosophy and literature from Copernicus to H.G. Wells / Karl S. Guthke. Utopian vision, technological innovation and poetic imagination.(1990).
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रGuthke, Karl S. "Are We Alone?: The Idea of Extraterrestrial Intelligence in Philosophy and Literature from Copernicus to H.G. Wells / Karl S. Guthke." Utopian Vision, Technological Innovation and Poetic Imagination.(1990) .
एमएलए (8वां संस्करण) प्रशस्ति पत्रGuthke, Karl S. "Are We Alone?: The Idea of Extraterrestrial Intelligence in Philosophy and Literature from Copernicus to H.G. Wells / Karl S. Guthke." Utopian Vision, Technological Innovation and Poetic Imagination.(1990), .
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