| APA | Smart Define. (1970). history of earth thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/history_of_earth/thesaurus/synonyms |
| Chicago | Smart Define. 1970. "history of earth thesaurus" https://smartdefine.org/history_of_earth/thesaurus/synonyms (accessed September 23, 2026). |
| Harvard | Smart Define 1970, history of earth thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/history_of_earth/thesaurus/synonyms>. |
| MLA | Smart Define. "history of earth thesaurus" 1 January 1970. Web. 23 September 2026. <https://smartdefine.org/history_of_earth/thesaurus/synonyms> |