https://www.cia.gov/readingroom/docs/DOC_0000042346.pdf
https://en.wikipedia.org/wiki/Voronezh_UFO_incident
https://english.pravda.ru/society/112049-dalnegorsk_ufo_crash/
https://www.nytimes.com/1989/10/11/world/ufo-landing-is-fact-not-fantasy-the-russians-insist.html
https://www.heraldscotland.com/news/12318039.alien-encounter-sparked-soviet-missile-crisis/
https://www.themoscowtimes.com/2016/03/31/us-and-russia-must-cooperate-to-prevent-nuclear-terrorism-a52348