| APA | OIPN. (2012, February 17). In Acronym Geek. Retrieved 00:33, February 17, 2012, from http://www.acronymgeek.com/OIPN |
| MLA | "OIPN." Acronym Geek. (2012). Acronym Geek. 17 Feb 2012 <http://www.acronymgeek.com/OIPN>. |
| MHRA | 'OIPN', Acronym Geek, 17 February 2012, <http://www.acronymgeek.com/OIPN> [accessed 17 February 2012] |
| Chicago | "OIPN", http://www.acronymgeek.com/OIPN (accessed February 17, 2012). |
| CBE/CSE | OIPN [Internet]. Acronym Geek; 2012 Feb 17 [cited 2012 Feb 17]. Available from: http://www.acronymgeek.com/OIPN. |
| Bluebook | OIPN, http://www.acronymgeek.com/OIPN (last visited February 17, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OIPN, http://www.acronymgeek.com/OIPN (optional description here) (as of Feb. 17, 2012, 00:33). |
| AMA | OIPN. Acronym Geek. February 17, 2012, 00:33. Available at: http://www.acronymgeek.com/OIPN. Accessed February 17, 2012, 00:33. |