| APA | Smart Define. (1970). nonbelieving doubtful thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/nonbelieving_doubtful/thesaurus/synonyms |
| Chicago | Smart Define. 1970. "nonbelieving doubtful thesaurus" https://smartdefine.org/nonbelieving_doubtful/thesaurus/synonyms (accessed September 26, 2026). |
| Harvard | Smart Define 1970, nonbelieving doubtful thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/nonbelieving_doubtful/thesaurus/synonyms>. |
| MLA | Smart Define. "nonbelieving doubtful thesaurus" 1 January 1970. Web. 26 September 2026. <https://smartdefine.org/nonbelieving_doubtful/thesaurus/synonyms> |