| APA | Smart Define. (2013). heydays thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/heydays/thesaurus/synonyms |
| Chicago | Smart Define. 2013. "heydays thesaurus" https://smartdefine.org/heydays/thesaurus/synonyms (accessed September 25, 2026). |
| Harvard | Smart Define 2013, heydays thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/heydays/thesaurus/synonyms>. |
| MLA | Smart Define. "heydays thesaurus" 19 May 2013. Web. 25 September 2026. <https://smartdefine.org/heydays/thesaurus/synonyms> |