| APA | OCO. (2012, February 10). In Acronym Geek. Retrieved 17:14, February 10, 2012, from http://www.acronymgeek.com/OCO |
| MLA | "OCO." Acronym Geek. (2012). Acronym Geek. 10 Feb 2012 <http://www.acronymgeek.com/OCO>. |
| MHRA | 'OCO', Acronym Geek, 10 February 2012, <http://www.acronymgeek.com/OCO> [accessed 10 February 2012] |
| Chicago | "OCO", http://www.acronymgeek.com/OCO (accessed February 10, 2012). |
| CBE/CSE | OCO [Internet]. Acronym Geek; 2012 Feb 10 [cited 2012 Feb 10]. Available from: http://www.acronymgeek.com/OCO. |
| Bluebook | OCO, http://www.acronymgeek.com/OCO (last visited February 10, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OCO, http://www.acronymgeek.com/OCO (optional description here) (as of Feb. 10, 2012, 17:14). |
| AMA | OCO. Acronym Geek. February 10, 2012, 17:14. Available at: http://www.acronymgeek.com/OCO. Accessed February 10, 2012, 17:14. |