| APA | Smart Define. (1970). sustainability of earth thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/sustainability_of_earth/thesaurus/broader |
| Chicago | Smart Define. 1970. "sustainability of earth thesaurus" https://smartdefine.org/sustainability_of_earth/thesaurus/broader (accessed September 25, 2026). |
| Harvard | Smart Define 1970, sustainability of earth thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/sustainability_of_earth/thesaurus/broader>. |
| MLA | Smart Define. "sustainability of earth thesaurus" 1 January 1970. Web. 25 September 2026. <https://smartdefine.org/sustainability_of_earth/thesaurus/broader> |