| APA | Smart Define. (1970). eco-unfriendly thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/eco-unfriendly/thesaurus/antonyms |
| Chicago | Smart Define. 1970. "eco-unfriendly thesaurus" https://smartdefine.org/eco-unfriendly/thesaurus/antonyms (accessed September 23, 2026). |
| Harvard | Smart Define 1970, eco-unfriendly thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/eco-unfriendly/thesaurus/antonyms>. |
| MLA | Smart Define. "eco-unfriendly thesaurus" 1 January 1970. Web. 23 September 2026. <https://smartdefine.org/eco-unfriendly/thesaurus/antonyms> |