| APA | Smart Define. (2013). letter-boxes thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/letter-boxes/thesaurus/related |
| Chicago | Smart Define. 2013. "letter-boxes thesaurus" https://smartdefine.org/letter-boxes/thesaurus/related (accessed September 24, 2026). |
| Harvard | Smart Define 2013, letter-boxes thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/letter-boxes/thesaurus/related>. |
| MLA | Smart Define. "letter-boxes thesaurus" 18 May 2013. Web. 24 September 2026. <https://smartdefine.org/letter-boxes/thesaurus/related> |