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