| APA | SOPI. (2012, February 10). In Acronym Geek. Retrieved 07:59, February 10, 2012, from http://www.acronymgeek.com/SOPI |
| MLA | "SOPI." Acronym Geek. (2012). Acronym Geek. 10 Feb 2012 <http://www.acronymgeek.com/SOPI>. |
| MHRA | 'SOPI', Acronym Geek, 10 February 2012, <http://www.acronymgeek.com/SOPI> [accessed 10 February 2012] |
| Chicago | "SOPI", http://www.acronymgeek.com/SOPI (accessed February 10, 2012). |
| CBE/CSE | SOPI [Internet]. Acronym Geek; 2012 Feb 10 [cited 2012 Feb 10]. Available from: http://www.acronymgeek.com/SOPI. |
| Bluebook | SOPI, http://www.acronymgeek.com/SOPI (last visited February 10, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, SOPI, http://www.acronymgeek.com/SOPI (optional description here) (as of Feb. 10, 2012, 07:59). |
| AMA | SOPI. Acronym Geek. February 10, 2012, 07:59. Available at: http://www.acronymgeek.com/SOPI. Accessed February 10, 2012, 07:59. |