优点，是宇宙交际的理想工具。另外还有专家认为,图象语言和音乐语言也可作为宇宙交际的共同语言。 Communications with Extraterrestrial Intelligence (PDF). Declassified Document, Department of Defense, USA

幽浮學

Science. July 1986. （原始内容 (PDF)存档于26 June 2007）. Communication With Extraterrestrial Intelligence (PDF). NSA. [2021-10-04]. （原始内容存档 (PDF)于2021-10-04）. Sir

道西基地

Press. 2003. ISBN 0-520-23805-2. Jerome Clark（英语：Jerome Clark）, The UFO Book: Encyclopedia of the Extraterrestrial, Visible Ink, 1998, ISBN 1-57859-029-9

Hemoglycin

life（英语：Evolutionary history of life） Extraterrestrial: The First Sign of Intelligent Life Beyond Earth（英语：Extraterrestrial: The First Sign of Intelligent Life

黑暗森林法則

2022）. Brin, G. D. The Great Silence - the Controversy Concerning Extraterrestrial Intelligent Life. Quarterly Journal of the Royal Astronomical Society

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宇宙语言