| APA | Smart Define. (2013). degree of difficulty thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/degree_of_difficulty/thesaurus/synonyms |
| Chicago | Smart Define. 2013. "degree of difficulty thesaurus" https://smartdefine.org/degree_of_difficulty/thesaurus/synonyms (accessed September 22, 2026). |
| Harvard | Smart Define 2013, degree of difficulty thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/degree_of_difficulty/thesaurus/synonyms>. |
| MLA | Smart Define. "degree of difficulty thesaurus" 18 May 2013. Web. 22 September 2026. <https://smartdefine.org/degree_of_difficulty/thesaurus/synonyms> |