| APA | Smart Define. (1970). painful serious thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/painful_serious/thesaurus/synonyms |
| Chicago | Smart Define. 1970. "painful serious thesaurus" https://smartdefine.org/painful_serious/thesaurus/synonyms (accessed September 30, 2026). |
| Harvard | Smart Define 1970, painful serious thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/painful_serious/thesaurus/synonyms>. |
| MLA | Smart Define. "painful serious thesaurus" 1 January 1970. Web. 30 September 2026. <https://smartdefine.org/painful_serious/thesaurus/synonyms> |