| APA | Smart Define. (1970). hop-o-my-thumb is the youngest thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/hop-o-my-thumb_is_the_youngest/thesaurus/broader |
| Chicago | Smart Define. 1970. "hop-o-my-thumb is the youngest thesaurus" https://smartdefine.org/hop-o-my-thumb_is_the_youngest/thesaurus/broader (accessed October 1, 2026). |
| Harvard | Smart Define 1970, hop-o-my-thumb is the youngest thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/hop-o-my-thumb_is_the_youngest/thesaurus/broader>. |
| MLA | Smart Define. "hop-o-my-thumb is the youngest thesaurus" 1 January 1970. Web. 1 October 2026. <https://smartdefine.org/hop-o-my-thumb_is_the_youngest/thesaurus/broader> |