| APA | Smart Define. (1970). natural features of the earth thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/natural_features_of_the_earth/thesaurus/synonyms |
| Chicago | Smart Define. 1970. "natural features of the earth thesaurus" https://smartdefine.org/natural_features_of_the_earth/thesaurus/synonyms (accessed October 1, 2026). |
| Harvard | Smart Define 1970, natural features of the earth thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/natural_features_of_the_earth/thesaurus/synonyms>. |
| MLA | Smart Define. "natural features of the earth thesaurus" 1 January 1970. Web. 1 October 2026. <https://smartdefine.org/natural_features_of_the_earth/thesaurus/synonyms> |