| APA | NPEO. (2012, February 14). In Acronym Geek. Retrieved 17:53, February 14, 2012, from http://www.acronymgeek.com/NPEO |
| MLA | "NPEO." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/NPEO>. |
| MHRA | 'NPEO', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/NPEO> [accessed 14 February 2012] |
| Chicago | "NPEO", http://www.acronymgeek.com/NPEO (accessed February 14, 2012). |
| CBE/CSE | NPEO [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/NPEO. |
| Bluebook | NPEO, http://www.acronymgeek.com/NPEO (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, NPEO, http://www.acronymgeek.com/NPEO (optional description here) (as of Feb. 14, 2012, 17:53). |
| AMA | NPEO. Acronym Geek. February 14, 2012, 17:53. Available at: http://www.acronymgeek.com/NPEO. Accessed February 14, 2012, 17:53. |