| APA | Smart Define. (2015). pioneer thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/pioneer/thesaurus/narrower |
| Chicago | Smart Define. 2015. "pioneer thesaurus" https://smartdefine.org/pioneer/thesaurus/narrower (accessed September 28, 2026). |
| Harvard | Smart Define 2015, pioneer thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/pioneer/thesaurus/narrower>. |
| MLA | Smart Define. "pioneer thesaurus" 17 December 2015. Web. 28 September 2026. <https://smartdefine.org/pioneer/thesaurus/narrower> |