| APA | Smart Define. (2011). tough and flexible thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/tough_and_flexible/thesaurus/synonyms |
| Chicago | Smart Define. 2011. "tough and flexible thesaurus" https://smartdefine.org/tough_and_flexible/thesaurus/synonyms (accessed September 30, 2026). |
| Harvard | Smart Define 2011, tough and flexible thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/tough_and_flexible/thesaurus/synonyms>. |
| MLA | Smart Define. "tough and flexible thesaurus" 29 May 2011. Web. 30 September 2026. <https://smartdefine.org/tough_and_flexible/thesaurus/synonyms> |