| APA | Smart Define. (2013). firm and indomitable thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/firm_and_indomitable/thesaurus/synonyms |
| Chicago | Smart Define. 2013. "firm and indomitable thesaurus" https://smartdefine.org/firm_and_indomitable/thesaurus/synonyms (accessed September 22, 2026). |
| Harvard | Smart Define 2013, firm and indomitable thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/firm_and_indomitable/thesaurus/synonyms>. |
| MLA | Smart Define. "firm and indomitable thesaurus" 18 May 2013. Web. 22 September 2026. <https://smartdefine.org/firm_and_indomitable/thesaurus/synonyms> |