| APA | Smart Define. (2016). doubtful phrase thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/doubtful_phrase/thesaurus/synonyms |
| Chicago | Smart Define. 2016. "doubtful phrase thesaurus" https://smartdefine.org/doubtful_phrase/thesaurus/synonyms (accessed September 20, 2026). |
| Harvard | Smart Define 2016, doubtful phrase thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/doubtful_phrase/thesaurus/synonyms>. |
| MLA | Smart Define. "doubtful phrase thesaurus" 29 February 2016. Web. 20 September 2026. <https://smartdefine.org/doubtful_phrase/thesaurus/synonyms> |