Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). grum. Retrieved September 22, 2026, from http://smartdefine.org/grum/definitions/2013953 |
| Chicago | Webster's. 2011. "grum" http://smartdefine.org/grum/definitions/2013953 (accessed September 22, 2026). |
| Harvard | Webster's 2011, grum, Smart Define, viewed 22 September, 2026, <http://smartdefine.org/grum/definitions/2013953>. |
| MLA | Webster's. "grum" 27 May 2011. Web. 22 September 2026. <http://smartdefine.org/grum/definitions/2013953> |