| APA | Smart Define. (2015). indo-european language thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/indo-european_language/thesaurus/narrower |
| Chicago | Smart Define. 2015. "indo-european language thesaurus" https://smartdefine.org/indo-european_language/thesaurus/narrower (accessed October 1, 2026). |
| Harvard | Smart Define 2015, indo-european language thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/indo-european_language/thesaurus/narrower>. |
| MLA | Smart Define. "indo-european language thesaurus" 14 April 2015. Web. 1 October 2026. <https://smartdefine.org/indo-european_language/thesaurus/narrower> |