Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). proin. Retrieved September 26, 2026, from http://smartdefine.org/proin/definitions/2049672 |
| Chicago | Webster's. 2011. "proin" http://smartdefine.org/proin/definitions/2049672 (accessed September 26, 2026). |
| Harvard | Webster's 2011, proin, Smart Define, viewed 26 September, 2026, <http://smartdefine.org/proin/definitions/2049672>. |
| MLA | Webster's. "proin" 27 May 2011. Web. 26 September 2026. <http://smartdefine.org/proin/definitions/2049672> |