| APA | Smart Define. (1970). ridge-and-valley appalachians thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/ridge-and-valley_appalachians/thesaurus/broader |
| Chicago | Smart Define. 1970. "ridge-and-valley appalachians thesaurus" https://smartdefine.org/ridge-and-valley_appalachians/thesaurus/broader (accessed October 1, 2026). |
| Harvard | Smart Define 1970, ridge-and-valley appalachians thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/ridge-and-valley_appalachians/thesaurus/broader>. |
| MLA | Smart Define. "ridge-and-valley appalachians thesaurus" 1 January 1970. Web. 1 October 2026. <https://smartdefine.org/ridge-and-valley_appalachians/thesaurus/broader> |