| APA | Smart Define. (2011). pithecanthropus erectus thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/pithecanthropus_erectus/thesaurus/synonyms |
| Chicago | Smart Define. 2011. "pithecanthropus erectus thesaurus" https://smartdefine.org/pithecanthropus_erectus/thesaurus/synonyms (accessed September 22, 2026). |
| Harvard | Smart Define 2011, pithecanthropus erectus thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/pithecanthropus_erectus/thesaurus/synonyms>. |
| MLA | Smart Define. "pithecanthropus erectus thesaurus" 26 April 2011. Web. 22 September 2026. <https://smartdefine.org/pithecanthropus_erectus/thesaurus/synonyms> |