| APA | Smart Define. (2011). charles robert darwin thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/charles_robert_darwin/thesaurus/synonyms |
| Chicago | Smart Define. 2011. "charles robert darwin thesaurus" https://smartdefine.org/charles_robert_darwin/thesaurus/synonyms (accessed September 21, 2026). |
| Harvard | Smart Define 2011, charles robert darwin thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/charles_robert_darwin/thesaurus/synonyms>. |
| MLA | Smart Define. "charles robert darwin thesaurus" 26 April 2011. Web. 21 September 2026. <https://smartdefine.org/charles_robert_darwin/thesaurus/synonyms> |