| APA | Smart Define. (2015). observance thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/observance/thesaurus/narrower |
| Chicago | Smart Define. 2015. "observance thesaurus" https://smartdefine.org/observance/thesaurus/narrower (accessed September 23, 2026). |
| Harvard | Smart Define 2015, observance thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/observance/thesaurus/narrower>. |
| MLA | Smart Define. "observance thesaurus" 23 December 2015. Web. 23 September 2026. <https://smartdefine.org/observance/thesaurus/narrower> |