↑ Denzler, Brenda (2003). The lure of the edge: scientific passions, religious beliefs, and the pursuit of UFOs. University of California Press. m/s. 6–7. ISBN0-520-23905-9.
↑ "The Air Force Intelligence Report". Dicapai May 3, 2010. To implement this policy it was directed that Hq, Air Material Command set up a project with the purpose of collecting, collating, evaluating, and distributing to interested government agencies and contractors, all information concerning sightings and phenomena in the atmosphere which could be construed to be of concern to the national security.
