| APA | Smart Define. (2016). youthful thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/youthful/thesaurus/antonyms |
| Chicago | Smart Define. 2016. "youthful thesaurus" https://smartdefine.org/youthful/thesaurus/antonyms (accessed October 1, 2026). |
| Harvard | Smart Define 2016, youthful thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/youthful/thesaurus/antonyms>. |
| MLA | Smart Define. "youthful thesaurus" 29 February 2016. Web. 1 October 2026. <https://smartdefine.org/youthful/thesaurus/antonyms> |