| APA | Smart Define. (2011). extraterrestrial object thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/extraterrestrial_object/thesaurus/narrower |
| Chicago | Smart Define. 2011. "extraterrestrial object thesaurus" https://smartdefine.org/extraterrestrial_object/thesaurus/narrower (accessed September 22, 2026). |
| Harvard | Smart Define 2011, extraterrestrial object thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/extraterrestrial_object/thesaurus/narrower>. |
| MLA | Smart Define. "extraterrestrial object thesaurus" 26 April 2011. Web. 22 September 2026. <https://smartdefine.org/extraterrestrial_object/thesaurus/narrower> |