| APA | Smart Define. (2011). tube-shaped structure thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/tube-shaped_structure/thesaurus/narrower |
| Chicago | Smart Define. 2011. "tube-shaped structure thesaurus" https://smartdefine.org/tube-shaped_structure/thesaurus/narrower (accessed September 27, 2026). |
| Harvard | Smart Define 2011, tube-shaped structure thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/tube-shaped_structure/thesaurus/narrower>. |
| MLA | Smart Define. "tube-shaped structure thesaurus" 26 April 2011. Web. 27 September 2026. <https://smartdefine.org/tube-shaped_structure/thesaurus/narrower> |