Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). hard-shell. Retrieved September 20, 2026, from http://smartdefine.org/hard-shell/definitions/2015024 |
| Chicago | Webster's. 2011. "hard-shell" http://smartdefine.org/hard-shell/definitions/2015024 (accessed September 20, 2026). |
| Harvard | Webster's 2011, hard-shell, Smart Define, viewed 20 September, 2026, <http://smartdefine.org/hard-shell/definitions/2015024>. |
| MLA | Webster's. "hard-shell" 27 May 2011. Web. 20 September 2026. <http://smartdefine.org/hard-shell/definitions/2015024> |