| APA | OPUE. (2012, February 15). In Acronym Geek. Retrieved 00:16, February 15, 2012, from http://www.acronymgeek.com/OPUE |
| MLA | "OPUE." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/OPUE>. |
| MHRA | 'OPUE', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/OPUE> [accessed 15 February 2012] |
| Chicago | "OPUE", http://www.acronymgeek.com/OPUE (accessed February 15, 2012). |
| CBE/CSE | OPUE [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/OPUE. |
| Bluebook | OPUE, http://www.acronymgeek.com/OPUE (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OPUE, http://www.acronymgeek.com/OPUE (optional description here) (as of Feb. 15, 2012, 00:16). |
| AMA | OPUE. Acronym Geek. February 15, 2012, 00:16. Available at: http://www.acronymgeek.com/OPUE. Accessed February 15, 2012, 00:16. |