| APA | Smart Define. (2013). ultraefficient thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/ultraefficient/thesaurus/antonyms |
| Chicago | Smart Define. 2013. "ultraefficient thesaurus" https://smartdefine.org/ultraefficient/thesaurus/antonyms (accessed September 21, 2026). |
| Harvard | Smart Define 2013, ultraefficient thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/ultraefficient/thesaurus/antonyms>. |
| MLA | Smart Define. "ultraefficient thesaurus" 28 June 2013. Web. 21 September 2026. <https://smartdefine.org/ultraefficient/thesaurus/antonyms> |