| APA | Smart Define. (2015). gravity-operated railway thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/gravity-operated_railway/thesaurus/synonyms |
| Chicago | Smart Define. 2015. "gravity-operated railway thesaurus" https://smartdefine.org/gravity-operated_railway/thesaurus/synonyms (accessed September 28, 2026). |
| Harvard | Smart Define 2015, gravity-operated railway thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/gravity-operated_railway/thesaurus/synonyms>. |
| MLA | Smart Define. "gravity-operated railway thesaurus" 10 April 2015. Web. 28 September 2026. <https://smartdefine.org/gravity-operated_railway/thesaurus/synonyms> |