| APA | Smart Define. (2013). cause to sleep thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/cause_to_sleep/thesaurus/broader |
| Chicago | Smart Define. 2013. "cause to sleep thesaurus" https://smartdefine.org/cause_to_sleep/thesaurus/broader (accessed September 24, 2026). |
| Harvard | Smart Define 2013, cause to sleep thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/cause_to_sleep/thesaurus/broader>. |
| MLA | Smart Define. "cause to sleep thesaurus" 28 June 2013. Web. 24 September 2026. <https://smartdefine.org/cause_to_sleep/thesaurus/broader> |