| APA | Smart Define. (2016). gruelling thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/gruelling/thesaurus/related |
| Chicago | Smart Define. 2016. "gruelling thesaurus" https://smartdefine.org/gruelling/thesaurus/related (accessed September 29, 2026). |
| Harvard | Smart Define 2016, gruelling thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/gruelling/thesaurus/related>. |
| MLA | Smart Define. "gruelling thesaurus" 26 February 2016. Web. 29 September 2026. <https://smartdefine.org/gruelling/thesaurus/related> |