| APA | Smart Define. (2015). decline of life thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/decline_of_life/thesaurus/related |
| Chicago | Smart Define. 2015. "decline of life thesaurus" https://smartdefine.org/decline_of_life/thesaurus/related (accessed September 30, 2026). |
| Harvard | Smart Define 2015, decline of life thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/decline_of_life/thesaurus/related>. |
| MLA | Smart Define. "decline of life thesaurus" 14 April 2015. Web. 30 September 2026. <https://smartdefine.org/decline_of_life/thesaurus/related> |