| APA | Smart Define. (2013). close in upon thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/close_in_upon/thesaurus/synonyms |
| Chicago | Smart Define. 2013. "close in upon thesaurus" https://smartdefine.org/close_in_upon/thesaurus/synonyms (accessed September 24, 2026). |
| Harvard | Smart Define 2013, close in upon thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/close_in_upon/thesaurus/synonyms>. |
| MLA | Smart Define. "close in upon thesaurus" 19 May 2013. Web. 24 September 2026. <https://smartdefine.org/close_in_upon/thesaurus/synonyms> |