| APA | Smart Define. (2015). eighteenth greek letter thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/eighteenth_greek_letter/thesaurus/synonyms |
| Chicago | Smart Define. 2015. "eighteenth greek letter thesaurus" https://smartdefine.org/eighteenth_greek_letter/thesaurus/synonyms (accessed October 1, 2026). |
| Harvard | Smart Define 2015, eighteenth greek letter thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/eighteenth_greek_letter/thesaurus/synonyms>. |
| MLA | Smart Define. "eighteenth greek letter thesaurus" 14 April 2015. Web. 1 October 2026. <https://smartdefine.org/eighteenth_greek_letter/thesaurus/synonyms> |