| APA | Smart Define. (1970). helium-four thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/helium-four/thesaurus/broader |
| Chicago | Smart Define. 1970. "helium-four thesaurus" https://smartdefine.org/helium-four/thesaurus/broader (accessed September 21, 2026). |
| Harvard | Smart Define 1970, helium-four thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/helium-four/thesaurus/broader>. |
| MLA | Smart Define. "helium-four thesaurus" 1 January 1970. Web. 21 September 2026. <https://smartdefine.org/helium-four/thesaurus/broader> |