Lähteet:
Tapani Kuningas: Muukalaisia ja humanoideja - suomalaisia havaintoja (1973)
https://blog.nationalarchives.gov.uk/unidentified-christmas-lights-stars-in-sky/
https://www.thedailybeast.com/why-theres-a-good-chance-youll-see-a-ufo-this-christmas/
https://www.cbc.ca/news/canada/manitoba/santa-ufo-christmas-reports-canada-1.5850393