^Communication With Extraterrestrial Intelligence(PDF). NSA. [2021-10-04]. (原始内容存档(PDF)于2021-10-04). Sir Bernard Lovell, one of the world's leading radio astronomers, has calculated that, even allowing for a margin of error of 5000%, there must be in our own galaxy about 100 million stars which have planets of the right chemistry, dimensions, and temperature to support organic evolution.
^ 11.011.1Peter Gersten, Frontiers of Science. What the U.S. Government Knows About UnidentifiedFlying Objects(PDF). NSA. [2021-08-18]. (原始内容存档(PDF)于2021-07-09). New evidence for the existence of unconventional aerial objects relies no longer on the credibility of civilian reports but on the records of scientists, military personnel, intelligence analysts, law enforcement officers and other reliable and responsible people. Their testimony can be found in three thousand pages of previously classified documents on UFOs released (mostly through Freedom of Information Act suits) over the past few years by the Departments of State / Army / Navy /Air Force/Defense, the Federal Bureau of Investigation, the National Securitv Agency, the Detense Intelligence Agency and the central Intelligence Agency.
^Edward U.Condon. Scientific Study of Unidentified Flying Objects. 1968 [May 4, 2010]. (原始内容存档于2017-09-12). Our general conclusion is that nothing has come from the study of UFOs in the past 21 years that has added to scientific knowledge. Careful consideration of the record as it is available to us leads us to conclude that further extensive study of UFOs probably cannot be justified in the expectation that science will be advanced thereby.
^Ministry of Defense. Unidentified Aerial Phenomena in the UK Air Defence Region: Executive Summary(PDF): 4. December 2000 [May 5, 2010]. (原始内容存档(PDF)于2012-10-26). That UAP exist is indisputable …[they] clearly can exhibit aerodynamic characteristics well beyond those of any known aircraft or missile – either manned or unmanned.
^Communication With Extraterrestrial Intelligence(PDF). NSA. [2021-08-18]. (原始内容存档(PDF)于2021-07-09). Sir Bernard Lovell, one of the world's leading radio astronomers, has calculated that, even allowing for a margin of error of 5000%, there must be in our own galaxy about 100 million stars which have planets of the right chemistry, dimensions, and temperature to support organic evolution.
Diana Palmer Hoyt, "UFOCRITIQUE: UFO's, Social Intelligence and the Condon Committee"; Master's Thesis, Virginia Polytechnic Institute, 2000 read it online