| APA | ONPI. (2012, February 14). In Acronym Geek. Retrieved 15:55, February 14, 2012, from http://www.acronymgeek.com/ONPI |
| MLA | "ONPI." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/ONPI>. |
| MHRA | 'ONPI', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/ONPI> [accessed 14 February 2012] |
| Chicago | "ONPI", http://www.acronymgeek.com/ONPI (accessed February 14, 2012). |
| CBE/CSE | ONPI [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/ONPI. |
| Bluebook | ONPI, http://www.acronymgeek.com/ONPI (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, ONPI, http://www.acronymgeek.com/ONPI (optional description here) (as of Feb. 14, 2012, 15:55). |
| AMA | ONPI. Acronym Geek. February 14, 2012, 15:55. Available at: http://www.acronymgeek.com/ONPI. Accessed February 14, 2012, 15:55. |