| APA | Smart Define. (2015). discrete four-channel system thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/discrete_four-channel_system/thesaurus/synonyms |
| Chicago | Smart Define. 2015. "discrete four-channel system thesaurus" https://smartdefine.org/discrete_four-channel_system/thesaurus/synonyms (accessed September 30, 2026). |
| Harvard | Smart Define 2015, discrete four-channel system thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/discrete_four-channel_system/thesaurus/synonyms>. |
| MLA | Smart Define. "discrete four-channel system thesaurus" 13 April 2015. Web. 30 September 2026. <https://smartdefine.org/discrete_four-channel_system/thesaurus/synonyms> |