| APA | Smart Define. (1970). douglas fir and aspen forest thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/douglas_fir_and_aspen_forest/thesaurus/broader |
| Chicago | Smart Define. 1970. "douglas fir and aspen forest thesaurus" https://smartdefine.org/douglas_fir_and_aspen_forest/thesaurus/broader (accessed September 27, 2026). |
| Harvard | Smart Define 1970, douglas fir and aspen forest thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/douglas_fir_and_aspen_forest/thesaurus/broader>. |
| MLA | Smart Define. "douglas fir and aspen forest thesaurus" 1 January 1970. Web. 27 September 2026. <https://smartdefine.org/douglas_fir_and_aspen_forest/thesaurus/broader> |