| APA | Smart Define. (2015). penetration thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/penetration/thesaurus/narrower |
| Chicago | Smart Define. 2015. "penetration thesaurus" https://smartdefine.org/penetration/thesaurus/narrower (accessed September 23, 2026). |
| Harvard | Smart Define 2015, penetration thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/penetration/thesaurus/narrower>. |
| MLA | Smart Define. "penetration thesaurus" 22 December 2015. Web. 23 September 2026. <https://smartdefine.org/penetration/thesaurus/narrower> |