| APA | Smart Define. (2011). national park service thesaurus. Retrieved October 2, 2026, from https://smartdefine.org/national_park_service/thesaurus/broader |
| Chicago | Smart Define. 2011. "national park service thesaurus" https://smartdefine.org/national_park_service/thesaurus/broader (accessed October 2, 2026). |
| Harvard | Smart Define 2011, national park service thesaurus, Smart Define, viewed 2 October, 2026, <https://smartdefine.org/national_park_service/thesaurus/broader>. |
| MLA | Smart Define. "national park service thesaurus" 26 April 2011. Web. 2 October 2026. <https://smartdefine.org/national_park_service/thesaurus/broader> |