Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). echoscope. Retrieved September 22, 2026, from http://smartdefine.org/echoscope/definitions/2001489 |
| Chicago | Webster's. 2011. "echoscope" http://smartdefine.org/echoscope/definitions/2001489 (accessed September 22, 2026). |
| Harvard | Webster's 2011, echoscope, Smart Define, viewed 22 September, 2026, <http://smartdefine.org/echoscope/definitions/2001489>. |
| MLA | Webster's. "echoscope" 27 May 2011. Web. 22 September 2026. <http://smartdefine.org/echoscope/definitions/2001489> |