Fonti

• http://www.inspiegabile.com
• http://it.wikipedia.org/
• http://en.wikipedia.org/
• http://www.acam.it/
• http://www.cicap.org/
• http://newapocalypse.altervista.org/
• http://www.ancient-wisdom.co.uk/
• http://en.wikipedia.org/wiki/Unidentified_flying_object
• http://en.wikipedia.org/wiki/Ufology