| APA | PDDN. (2012, February 16). In Acronym Geek. Retrieved 01:40, February 16, 2012, from http://www.acronymgeek.com/PDDN |
| MLA | "PDDN." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/PDDN>. |
| MHRA | 'PDDN', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/PDDN> [accessed 16 February 2012] |
| Chicago | "PDDN", http://www.acronymgeek.com/PDDN (accessed February 16, 2012). |
| CBE/CSE | PDDN [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/PDDN. |
| Bluebook | PDDN, http://www.acronymgeek.com/PDDN (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PDDN, http://www.acronymgeek.com/PDDN (optional description here) (as of Feb. 16, 2012, 01:40). |
| AMA | PDDN. Acronym Geek. February 16, 2012, 01:40. Available at: http://www.acronymgeek.com/PDDN. Accessed February 16, 2012, 01:40. |