| APA | PORO. (2012, February 16). In Acronym Geek. Retrieved 06:55, February 16, 2012, from http://www.acronymgeek.com/PORO |
| MLA | "PORO." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/PORO>. |
| MHRA | 'PORO', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/PORO> [accessed 16 February 2012] |
| Chicago | "PORO", http://www.acronymgeek.com/PORO (accessed February 16, 2012). |
| CBE/CSE | PORO [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/PORO. |
| Bluebook | PORO, http://www.acronymgeek.com/PORO (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PORO, http://www.acronymgeek.com/PORO (optional description here) (as of Feb. 16, 2012, 06:55). |
| AMA | PORO. Acronym Geek. February 16, 2012, 06:55. Available at: http://www.acronymgeek.com/PORO. Accessed February 16, 2012, 06:55. |