| APA | Smart Define. (2013). sign of past thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/sign_of_past/thesaurus/related |
| Chicago | Smart Define. 2013. "sign of past thesaurus" https://smartdefine.org/sign_of_past/thesaurus/related (accessed September 30, 2026). |
| Harvard | Smart Define 2013, sign of past thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/sign_of_past/thesaurus/related>. |
| MLA | Smart Define. "sign of past thesaurus" 17 May 2013. Web. 30 September 2026. <https://smartdefine.org/sign_of_past/thesaurus/related> |