| APA | Smart Define. (1970). environmentally harmful thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/environmentally_harmful/thesaurus/antonyms |
| Chicago | Smart Define. 1970. "environmentally harmful thesaurus" https://smartdefine.org/environmentally_harmful/thesaurus/antonyms (accessed September 24, 2026). |
| Harvard | Smart Define 1970, environmentally harmful thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/environmentally_harmful/thesaurus/antonyms>. |
| MLA | Smart Define. "environmentally harmful thesaurus" 1 January 1970. Web. 24 September 2026. <https://smartdefine.org/environmentally_harmful/thesaurus/antonyms> |