Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). neptunian. Retrieved September 20, 2026, from http://smartdefine.org/neptunian/definitions/2036422 |
| Chicago | Webster's. 2011. "neptunian" http://smartdefine.org/neptunian/definitions/2036422 (accessed September 20, 2026). |
| Harvard | Webster's 2011, neptunian, Smart Define, viewed 20 September, 2026, <http://smartdefine.org/neptunian/definitions/2036422>. |
| MLA | Webster's. "neptunian" 27 May 2011. Web. 20 September 2026. <http://smartdefine.org/neptunian/definitions/2036422> |