| APA | NPKI. (2012, February 14). In Acronym Geek. Retrieved 00:32, February 14, 2012, from http://www.acronymgeek.com/NPKI |
| MLA | "NPKI." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/NPKI>. |
| MHRA | 'NPKI', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/NPKI> [accessed 14 February 2012] |
| Chicago | "NPKI", http://www.acronymgeek.com/NPKI (accessed February 14, 2012). |
| CBE/CSE | NPKI [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/NPKI. |
| Bluebook | NPKI, http://www.acronymgeek.com/NPKI (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, NPKI, http://www.acronymgeek.com/NPKI (optional description here) (as of Feb. 14, 2012, 00:32). |
| AMA | NPKI. Acronym Geek. February 14, 2012, 00:32. Available at: http://www.acronymgeek.com/NPKI. Accessed February 14, 2012, 00:32. |