| APA | Smart Define. (2011). build castles in air thesaurus. Retrieved October 1, 2026, from https://smartdefine.org/build_castles_in_air/thesaurus/antonyms |
| Chicago | Smart Define. 2011. "build castles in air thesaurus" https://smartdefine.org/build_castles_in_air/thesaurus/antonyms (accessed October 1, 2026). |
| Harvard | Smart Define 2011, build castles in air thesaurus, Smart Define, viewed 1 October, 2026, <https://smartdefine.org/build_castles_in_air/thesaurus/antonyms>. |
| MLA | Smart Define. "build castles in air thesaurus" 24 May 2011. Web. 1 October 2026. <https://smartdefine.org/build_castles_in_air/thesaurus/antonyms> |