| APA | Smart Define. (2013). colour tube thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/colour_tube/thesaurus/narrower |
| Chicago | Smart Define. 2013. "colour tube thesaurus" https://smartdefine.org/colour_tube/thesaurus/narrower (accessed September 28, 2026). |
| Harvard | Smart Define 2013, colour tube thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/colour_tube/thesaurus/narrower>. |
| MLA | Smart Define. "colour tube thesaurus" 18 May 2013. Web. 28 September 2026. <https://smartdefine.org/colour_tube/thesaurus/narrower> |