| APA | Smart Define. (2013). keen in observation thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/keen_in_observation/thesaurus/related |
| Chicago | Smart Define. 2013. "keen in observation thesaurus" https://smartdefine.org/keen_in_observation/thesaurus/related (accessed October 1, 2026). |
| Harvard | Smart Define 2013, keen in observation thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/keen_in_observation/thesaurus/related>. |
| MLA | Smart Define. "keen in observation thesaurus" 18 May 2013. Web. 1 October 2026. <https://smartdefine.org/keen_in_observation/thesaurus/related> |