| APA | Smart Define. (2011). external-combustion engine thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/external-combustion_engine/thesaurus/narrower |
| Chicago | Smart Define. 2011. "external-combustion engine thesaurus" https://smartdefine.org/external-combustion_engine/thesaurus/narrower (accessed September 21, 2026). |
| Harvard | Smart Define 2011, external-combustion engine thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/external-combustion_engine/thesaurus/narrower>. |
| MLA | Smart Define. "external-combustion engine thesaurus" 26 April 2011. Web. 21 September 2026. <https://smartdefine.org/external-combustion_engine/thesaurus/narrower> |