| APA | Smart Define. (2011). variola virus thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/variola_virus/thesaurus/synonyms |
| Chicago | Smart Define. 2011. "variola virus thesaurus" https://smartdefine.org/variola_virus/thesaurus/synonyms (accessed September 21, 2026). |
| Harvard | Smart Define 2011, variola virus thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/variola_virus/thesaurus/synonyms>. |
| MLA | Smart Define. "variola virus thesaurus" 26 April 2011. Web. 21 September 2026. <https://smartdefine.org/variola_virus/thesaurus/synonyms> |