| APA | OPD. (2012, February 8). In Acronym Geek. Retrieved 12:10, February 8, 2012, from http://www.acronymgeek.com/OPD |
| MLA | "OPD." Acronym Geek. (2012). Acronym Geek. 8 Feb 2012 <http://www.acronymgeek.com/OPD>. |
| MHRA | 'OPD', Acronym Geek, 8 February 2012, <http://www.acronymgeek.com/OPD> [accessed 8 February 2012] |
| Chicago | "OPD", http://www.acronymgeek.com/OPD (accessed February 8, 2012). |
| CBE/CSE | OPD [Internet]. Acronym Geek; 2012 Feb 8 [cited 2012 Feb 8]. Available from: http://www.acronymgeek.com/OPD. |
| Bluebook | OPD, http://www.acronymgeek.com/OPD (last visited February 8, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OPD, http://www.acronymgeek.com/OPD (optional description here) (as of Feb. 8, 2012, 12:10). |
| AMA | OPD. Acronym Geek. February 8, 2012, 12:10. Available at: http://www.acronymgeek.com/OPD. Accessed February 8, 2012, 12:10. |