| APA | PO.. (2012, February 10). In Acronym Geek. Retrieved 09:45, February 10, 2012, from http://www.acronymgeek.com/PO. |
| MLA | "PO.." Acronym Geek. (2012). Acronym Geek. 10 Feb 2012 <http://www.acronymgeek.com/PO.>. |
| MHRA | 'PO.', Acronym Geek, 10 February 2012, <http://www.acronymgeek.com/PO.> [accessed 10 February 2012] |
| Chicago | "PO.", http://www.acronymgeek.com/PO. (accessed February 10, 2012). |
| CBE/CSE | PO. [Internet]. Acronym Geek; 2012 Feb 10 [cited 2012 Feb 10]. Available from: http://www.acronymgeek.com/PO.. |
| Bluebook | PO., http://www.acronymgeek.com/PO. (last visited February 10, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PO., http://www.acronymgeek.com/PO. (optional description here) (as of Feb. 10, 2012, 09:45). |
| AMA | PO.. Acronym Geek. February 10, 2012, 09:45. Available at: http://www.acronymgeek.com/PO.. Accessed February 10, 2012, 09:45. |