| APA | Smart Define. (2016). signal thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/signal/thesaurus/narrower |
| Chicago | Smart Define. 2016. "signal thesaurus" https://smartdefine.org/signal/thesaurus/narrower (accessed September 27, 2026). |
| Harvard | Smart Define 2016, signal thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/signal/thesaurus/narrower>. |
| MLA | Smart Define. "signal thesaurus" 1 March 2016. Web. 27 September 2026. <https://smartdefine.org/signal/thesaurus/narrower> |