| APA | Smart Define. (1970). timeline of vaccines thesaurus. Retrieved October 2, 2026, from https://smartdefine.org/timeline_of_vaccines/thesaurus/broader |
| Chicago | Smart Define. 1970. "timeline of vaccines thesaurus" https://smartdefine.org/timeline_of_vaccines/thesaurus/broader (accessed October 2, 2026). |
| Harvard | Smart Define 1970, timeline of vaccines thesaurus, Smart Define, viewed 2 October, 2026, <https://smartdefine.org/timeline_of_vaccines/thesaurus/broader>. |
| MLA | Smart Define. "timeline of vaccines thesaurus" 1 January 1970. Web. 2 October 2026. <https://smartdefine.org/timeline_of_vaccines/thesaurus/broader> |