| APA | Smart Define. (2013). tube railway thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/tube_railway/thesaurus/synonyms |
| Chicago | Smart Define. 2013. "tube railway thesaurus" https://smartdefine.org/tube_railway/thesaurus/synonyms (accessed September 28, 2026). |
| Harvard | Smart Define 2013, tube railway thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/tube_railway/thesaurus/synonyms>. |
| MLA | Smart Define. "tube railway thesaurus" 18 May 2013. Web. 28 September 2026. <https://smartdefine.org/tube_railway/thesaurus/synonyms> |