(en) Bruce Rux, Architects of the Underworld: Unriddling Atlantis, Anomalies of Mars, and the Mystery of the Sphinx, Frog Books, (ISBN978-1-883319-46-5, lire en ligne), p. 109–120.
(en) Brenda Denzler, The Lure of the Edge: Scientific Passions, Religious Beliefs, and the Pursuit of UFOs, University of California Press, (ISBN978-0-520-93027-8, lire en ligne), p. 51–.
(en) Mark Pilkington, Mirage Men: A Journey into Disinformation, Paranoia and UFOs., Constable & Robinson Limited, (ISBN978-1-84901-240-9, lire en ligne), p. 1950.
(en) David M. Jacobs, Secret Life: Firsthand, Documented Accounts of Ufo Abductions, Simon and Schuster, (ISBN978-1-4391-3677-5, lire en ligne), p. 39.
(en) Barna William Donovan, Conspiracy Films: A Tour of Dark Places in the American Conscious, McFarland, (ISBN978-0-7864-8615-1, lire en ligne), p. 54.
haaan.com
magonia.haaan.com
(en) Peter Rogerson, Notes towards a revisionist history of abductions – Part 1, in Magonia, No 46, June 1993 : « Researcher Peter Rogerson, however, doubts the veracity of Boas' story. He notes that several months before Boas first related his claims, a similar story was printed in the November 1957 issue of the periodical O Cruzeiro, and suggests that Boas borrowed details of this earlier account, along with elements of the contactee stories of George Adamski ».