| APA | Smart Define. (2011). friedrich engels thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/friedrich_engels/thesaurus/synonyms |
| Chicago | Smart Define. 2011. "friedrich engels thesaurus" https://smartdefine.org/friedrich_engels/thesaurus/synonyms (accessed September 24, 2026). |
| Harvard | Smart Define 2011, friedrich engels thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/friedrich_engels/thesaurus/synonyms>. |
| MLA | Smart Define. "friedrich engels thesaurus" 26 April 2011. Web. 24 September 2026. <https://smartdefine.org/friedrich_engels/thesaurus/synonyms> |