| APA | Smart Define. (1970). environmental study tour thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/environmental_study_tour/thesaurus/broader |
| Chicago | Smart Define. 1970. "environmental study tour thesaurus" https://smartdefine.org/environmental_study_tour/thesaurus/broader (accessed September 21, 2026). |
| Harvard | Smart Define 1970, environmental study tour thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/environmental_study_tour/thesaurus/broader>. |
| MLA | Smart Define. "environmental study tour thesaurus" 1 January 1970. Web. 21 September 2026. <https://smartdefine.org/environmental_study_tour/thesaurus/broader> |