| APA | PDE. (2012, February 14). In Acronym Geek. Retrieved 09:54, February 14, 2012, from http://www.acronymgeek.com/PDE |
| MLA | "PDE." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/PDE>. |
| MHRA | 'PDE', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/PDE> [accessed 14 February 2012] |
| Chicago | "PDE", http://www.acronymgeek.com/PDE (accessed February 14, 2012). |
| CBE/CSE | PDE [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/PDE. |
| Bluebook | PDE, http://www.acronymgeek.com/PDE (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PDE, http://www.acronymgeek.com/PDE (optional description here) (as of Feb. 14, 2012, 09:54). |
| AMA | PDE. Acronym Geek. February 14, 2012, 09:54. Available at: http://www.acronymgeek.com/PDE. Accessed February 14, 2012, 09:54. |