| APA | Smart Define. (2011). hard porn thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/hard_porn/thesaurus/narrower |
| Chicago | Smart Define. 2011. "hard porn thesaurus" https://smartdefine.org/hard_porn/thesaurus/narrower (accessed September 25, 2026). |
| Harvard | Smart Define 2011, hard porn thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/hard_porn/thesaurus/narrower>. |
| MLA | Smart Define. "hard porn thesaurus" 23 May 2011. Web. 25 September 2026. <https://smartdefine.org/hard_porn/thesaurus/narrower> |