| APA | ONPK. (2012, February 17). In Acronym Geek. Retrieved 00:26, February 17, 2012, from http://www.acronymgeek.com/ONPK |
| MLA | "ONPK." Acronym Geek. (2012). Acronym Geek. 17 Feb 2012 <http://www.acronymgeek.com/ONPK>. |
| MHRA | 'ONPK', Acronym Geek, 17 February 2012, <http://www.acronymgeek.com/ONPK> [accessed 17 February 2012] |
| Chicago | "ONPK", http://www.acronymgeek.com/ONPK (accessed February 17, 2012). |
| CBE/CSE | ONPK [Internet]. Acronym Geek; 2012 Feb 17 [cited 2012 Feb 17]. Available from: http://www.acronymgeek.com/ONPK. |
| Bluebook | ONPK, http://www.acronymgeek.com/ONPK (last visited February 17, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, ONPK, http://www.acronymgeek.com/ONPK (optional description here) (as of Feb. 17, 2012, 00:26). |
| AMA | ONPK. Acronym Geek. February 17, 2012, 00:26. Available at: http://www.acronymgeek.com/ONPK. Accessed February 17, 2012, 00:26. |