| APA | Smart Define. (2013). lens system thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/lens_system/thesaurus/narrower |
| Chicago | Smart Define. 2013. "lens system thesaurus" https://smartdefine.org/lens_system/thesaurus/narrower (accessed September 25, 2026). |
| Harvard | Smart Define 2013, lens system thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/lens_system/thesaurus/narrower>. |
| MLA | Smart Define. "lens system thesaurus" 18 May 2013. Web. 25 September 2026. <https://smartdefine.org/lens_system/thesaurus/narrower> |