| APA | Smart Define. (1970). productive efficiency thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/productive_efficiency/thesaurus/narrower |
| Chicago | Smart Define. 1970. "productive efficiency thesaurus" https://smartdefine.org/productive_efficiency/thesaurus/narrower (accessed September 21, 2026). |
| Harvard | Smart Define 1970, productive efficiency thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/productive_efficiency/thesaurus/narrower>. |
| MLA | Smart Define. "productive efficiency thesaurus" 1 January 1970. Web. 21 September 2026. <https://smartdefine.org/productive_efficiency/thesaurus/narrower> |