1. Stuart Appelle. The abduction experience: A critical evaluation of theory and evidence. Journal of UFO Studies, 1995/96(6):29–78, 1995/96. URL: https://files.afu.se/Downloads/Documents/0%20-%20UFO%20Researchers/NIDS/Website%20Material/Stuart%20Appelle%20-%20The%20Abduction%20Experience.pdf.
2. Stuart Appelle, Steven Jay Lynn, and Leonard Newman. Alien abduction experiences. In Varieties of anomalous experience: Examining the scientific evidence, pages 253–282. American Psychological Association, 2000. URL: https://doi.org/10.1037 https://doi.org/10.1037/10371-008
3. Annie Jacobsen. Area 51: An Uncensored History of America’s Top Secret Military Base. Back Bay Books, New York, NY, USA, 2011. URL: https://www.hachettebookgroup.com/titles/annie-jacobsen/area-51/9780316202305/.
4. Gerald K. Haines. CIA’s role in the study of UFOs, 1947–1990. A die-hard issue. Studies In Intelligence, 1(1):67–84, 1997. URL: https://www.cia.gov/resources/csi/studies-in-intelligence/studies-in-intelligence-1997/cias-role-in-the-study-of-ufos-1947-1990.
5. Mark Pilkington. Mirage Men: An Adventure into Paranoia, Espionage, Psychological Warfare, and UFOs. Skyhorse, New York, NY, USA, Sep 2010. URL: https://www.simonandschuster.com/books/Mirage-Men/Mark-Pilkington/9781602398009.