| APA | PD. (2012, February 14). In Acronym Geek. Retrieved 06:53, February 14, 2012, from http://www.acronymgeek.com/PD |
| MLA | "PD." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/PD>. |
| MHRA | 'PD', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/PD> [accessed 14 February 2012] |
| Chicago | "PD", http://www.acronymgeek.com/PD (accessed February 14, 2012). |
| CBE/CSE | PD [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/PD. |
| Bluebook | PD, http://www.acronymgeek.com/PD (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PD, http://www.acronymgeek.com/PD (optional description here) (as of Feb. 14, 2012, 06:53). |
| AMA | PD. Acronym Geek. February 14, 2012, 06:53. Available at: http://www.acronymgeek.com/PD. Accessed February 14, 2012, 06:53. |