| APA | OPUP. (2012, February 16). In Acronym Geek. Retrieved 14:55, February 16, 2012, from http://www.acronymgeek.com/OPUP |
| MLA | "OPUP." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/OPUP>. |
| MHRA | 'OPUP', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/OPUP> [accessed 16 February 2012] |
| Chicago | "OPUP", http://www.acronymgeek.com/OPUP (accessed February 16, 2012). |
| CBE/CSE | OPUP [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/OPUP. |
| Bluebook | OPUP, http://www.acronymgeek.com/OPUP (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OPUP, http://www.acronymgeek.com/OPUP (optional description here) (as of Feb. 16, 2012, 14:55). |
| AMA | OPUP. Acronym Geek. February 16, 2012, 14:55. Available at: http://www.acronymgeek.com/OPUP. Accessed February 16, 2012, 14:55. |