| APA | Smart Define. (2016). doubtful expression thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/doubtful_expression/thesaurus/antonyms |
| Chicago | Smart Define. 2016. "doubtful expression thesaurus" https://smartdefine.org/doubtful_expression/thesaurus/antonyms (accessed September 21, 2026). |
| Harvard | Smart Define 2016, doubtful expression thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/doubtful_expression/thesaurus/antonyms>. |
| MLA | Smart Define. "doubtful expression thesaurus" 29 February 2016. Web. 21 September 2026. <https://smartdefine.org/doubtful_expression/thesaurus/antonyms> |