| APA | Smart Define. (2011). letter of the alphabet thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/letter_of_the_alphabet/thesaurus/narrower |
| Chicago | Smart Define. 2011. "letter of the alphabet thesaurus" https://smartdefine.org/letter_of_the_alphabet/thesaurus/narrower (accessed October 1, 2026). |
| Harvard | Smart Define 2011, letter of the alphabet thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/letter_of_the_alphabet/thesaurus/narrower>. |
| MLA | Smart Define. "letter of the alphabet thesaurus" 26 April 2011. Web. 1 October 2026. <https://smartdefine.org/letter_of_the_alphabet/thesaurus/narrower> |