| APA | Smart Define. (2013). upper-crust thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/upper-crust/thesaurus/antonyms |
| Chicago | Smart Define. 2013. "upper-crust thesaurus" https://smartdefine.org/upper-crust/thesaurus/antonyms (accessed September 24, 2026). |
| Harvard | Smart Define 2013, upper-crust thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/upper-crust/thesaurus/antonyms>. |
| MLA | Smart Define. "upper-crust thesaurus" 28 June 2013. Web. 24 September 2026. <https://smartdefine.org/upper-crust/thesaurus/antonyms> |