| APA | Smart Define. (1970). sustainability challenges remain thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/sustainability_challenges_remain/thesaurus/broader |
| Chicago | Smart Define. 1970. "sustainability challenges remain thesaurus" https://smartdefine.org/sustainability_challenges_remain/thesaurus/broader (accessed September 24, 2026). |
| Harvard | Smart Define 1970, sustainability challenges remain thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/sustainability_challenges_remain/thesaurus/broader>. |
| MLA | Smart Define. "sustainability challenges remain thesaurus" 1 January 1970. Web. 24 September 2026. <https://smartdefine.org/sustainability_challenges_remain/thesaurus/broader> |