| APA | Smart Define. (1970). closing of a letter thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/closing_of_a_letter/thesaurus/narrower |
| Chicago | Smart Define. 1970. "closing of a letter thesaurus" https://smartdefine.org/closing_of_a_letter/thesaurus/narrower (accessed September 26, 2026). |
| Harvard | Smart Define 1970, closing of a letter thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/closing_of_a_letter/thesaurus/narrower>. |
| MLA | Smart Define. "closing of a letter thesaurus" 1 January 1970. Web. 26 September 2026. <https://smartdefine.org/closing_of_a_letter/thesaurus/narrower> |