| APA | Smart Define. (2015). difficulty thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/difficulty/thesaurus/related |
| Chicago | Smart Define. 2015. "difficulty thesaurus" https://smartdefine.org/difficulty/thesaurus/related (accessed September 20, 2026). |
| Harvard | Smart Define 2015, difficulty thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/difficulty/thesaurus/related>. |
| MLA | Smart Define. "difficulty thesaurus" 23 December 2015. Web. 20 September 2026. <https://smartdefine.org/difficulty/thesaurus/related> |