| APA | NPDU. (2012, February 16). In Acronym Geek. Retrieved 22:19, February 16, 2012, from http://www.acronymgeek.com/NPDU |
| MLA | "NPDU." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/NPDU>. |
| MHRA | 'NPDU', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/NPDU> [accessed 16 February 2012] |
| Chicago | "NPDU", http://www.acronymgeek.com/NPDU (accessed February 16, 2012). |
| CBE/CSE | NPDU [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/NPDU. |
| Bluebook | NPDU, http://www.acronymgeek.com/NPDU (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, NPDU, http://www.acronymgeek.com/NPDU (optional description here) (as of Feb. 16, 2012, 22:19). |
| AMA | NPDU. Acronym Geek. February 16, 2012, 22:19. Available at: http://www.acronymgeek.com/NPDU. Accessed February 16, 2012, 22:19. |