*{{cite book |last = Condon |first = Edward Uhler |authorlink = Edward Uhler Condon |coauthors = |title = Final Report of the Scientific Study of Unidentified Flying Objects |publisher = Dutton |date = 1969 |location = |page = 505 |url = |doi = |id = |isbn = }}
*{{cite book |last = Clark |first = Jerome |authorlink = Jerome Clark |coauthors = |title = The UFO Encyclopedia: The Phenomenon from the Beginning |publisher = Omnigraphics |date = 1998 |location = Detroit |pages = 452–453 |url = |doi = |id = |isbn = 0-7808-0097-4}}
*{{cite book |last = Peebles |first = Curtis |authorlink = |coauthors = |title = Watch the Skies: A Chronicle of the Flying Saucer Myth |publisher = Berkley Books |date = 1995 |location = New York |pages = 29–31 |url = |doi = |id = |isbn = 0-425-15117-4}}
*{{cite book |last = Ruppelt |first = Edward J. |authorlink = Edward J. Ruppelt |coauthors = |title = The Report on Unidentified Flying Objects |publisher = Doubleday & Company |date = 1956 |location = Garden City, New York |pages = 30–31 |url = http://www.gutenberg.org/etext/17346 |doi = |id = |isbn = }}
