| APA | Smart Define. (2013). tunnelling thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/tunnelling/thesaurus/related |
| Chicago | Smart Define. 2013. "tunnelling thesaurus" https://smartdefine.org/tunnelling/thesaurus/related (accessed September 25, 2026). |
| Harvard | Smart Define 2013, tunnelling thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/tunnelling/thesaurus/related>. |
| MLA | Smart Define. "tunnelling thesaurus" 19 May 2013. Web. 25 September 2026. <https://smartdefine.org/tunnelling/thesaurus/related> |