| APA | Smart Define. (2013). heart sinking thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/heart_sinking/thesaurus/synonyms |
| Chicago | Smart Define. 2013. "heart sinking thesaurus" https://smartdefine.org/heart_sinking/thesaurus/synonyms (accessed September 20, 2026). |
| Harvard | Smart Define 2013, heart sinking thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/heart_sinking/thesaurus/synonyms>. |
| MLA | Smart Define. "heart sinking thesaurus" 18 May 2013. Web. 20 September 2026. <https://smartdefine.org/heart_sinking/thesaurus/synonyms> |