| APA | Smart Define. (1970). investigation of natural phenomena thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/investigation_of_natural_phenomena/thesaurus/narrower |
| Chicago | Smart Define. 1970. "investigation of natural phenomena thesaurus" https://smartdefine.org/investigation_of_natural_phenomena/thesaurus/narrower (accessed September 26, 2026). |
| Harvard | Smart Define 1970, investigation of natural phenomena thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/investigation_of_natural_phenomena/thesaurus/narrower>. |
| MLA | Smart Define. "investigation of natural phenomena thesaurus" 1 January 1970. Web. 26 September 2026. <https://smartdefine.org/investigation_of_natural_phenomena/thesaurus/narrower> |