| APA | SOPU. (2012, February 11). In Acronym Geek. Retrieved 19:48, February 11, 2012, from http://www.acronymgeek.com/SOPU |
| MLA | "SOPU." Acronym Geek. (2012). Acronym Geek. 11 Feb 2012 <http://www.acronymgeek.com/SOPU>. |
| MHRA | 'SOPU', Acronym Geek, 11 February 2012, <http://www.acronymgeek.com/SOPU> [accessed 11 February 2012] |
| Chicago | "SOPU", http://www.acronymgeek.com/SOPU (accessed February 11, 2012). |
| CBE/CSE | SOPU [Internet]. Acronym Geek; 2012 Feb 11 [cited 2012 Feb 11]. Available from: http://www.acronymgeek.com/SOPU. |
| Bluebook | SOPU, http://www.acronymgeek.com/SOPU (last visited February 11, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, SOPU, http://www.acronymgeek.com/SOPU (optional description here) (as of Feb. 11, 2012, 19:48). |
| AMA | SOPU. Acronym Geek. February 11, 2012, 19:48. Available at: http://www.acronymgeek.com/SOPU. Accessed February 11, 2012, 19:48. |