Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). opercula. Retrieved September 20, 2026, from http://smartdefine.org/opercula/definitions/2038994 |
| Chicago | Webster's. 2011. "opercula" http://smartdefine.org/opercula/definitions/2038994 (accessed September 20, 2026). |
| Harvard | Webster's 2011, opercula, Smart Define, viewed 20 September, 2026, <http://smartdefine.org/opercula/definitions/2038994>. |
| MLA | Webster's. "opercula" 27 May 2011. Web. 20 September 2026. <http://smartdefine.org/opercula/definitions/2038994> |