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