| APA | OPNZ. (2012, February 14). In Acronym Geek. Retrieved 20:11, February 14, 2012, from http://www.acronymgeek.com/OPNZ |
| MLA | "OPNZ." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/OPNZ>. |
| MHRA | 'OPNZ', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/OPNZ> [accessed 14 February 2012] |
| Chicago | "OPNZ", http://www.acronymgeek.com/OPNZ (accessed February 14, 2012). |
| CBE/CSE | OPNZ [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/OPNZ. |
| Bluebook | OPNZ, http://www.acronymgeek.com/OPNZ (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OPNZ, http://www.acronymgeek.com/OPNZ (optional description here) (as of Feb. 14, 2012, 20:11). |
| AMA | OPNZ. Acronym Geek. February 14, 2012, 20:11. Available at: http://www.acronymgeek.com/OPNZ. Accessed February 14, 2012, 20:11. |