| APA | UNDN. (2012, February 16). In Acronym Geek. Retrieved 00:03, February 16, 2012, from http://www.acronymgeek.com/UNDN |
| MLA | "UNDN." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/UNDN>. |
| MHRA | 'UNDN', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/UNDN> [accessed 16 February 2012] |
| Chicago | "UNDN", http://www.acronymgeek.com/UNDN (accessed February 16, 2012). |
| CBE/CSE | UNDN [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/UNDN. |
| Bluebook | UNDN, http://www.acronymgeek.com/UNDN (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, UNDN, http://www.acronymgeek.com/UNDN (optional description here) (as of Feb. 16, 2012, 00:03). |
| AMA | UNDN. Acronym Geek. February 16, 2012, 00:03. Available at: http://www.acronymgeek.com/UNDN. Accessed February 16, 2012, 00:03. |