| APA | SPDO. (2012, February 15). In Acronym Geek. Retrieved 23:20, February 15, 2012, from http://www.acronymgeek.com/SPDO |
| MLA | "SPDO." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/SPDO>. |
| MHRA | 'SPDO', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/SPDO> [accessed 15 February 2012] |
| Chicago | "SPDO", http://www.acronymgeek.com/SPDO (accessed February 15, 2012). |
| CBE/CSE | SPDO [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/SPDO. |
| Bluebook | SPDO, http://www.acronymgeek.com/SPDO (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, SPDO, http://www.acronymgeek.com/SPDO (optional description here) (as of Feb. 15, 2012, 23:20). |
| AMA | SPDO. Acronym Geek. February 15, 2012, 23:20. Available at: http://www.acronymgeek.com/SPDO. Accessed February 15, 2012, 23:20. |