| APA | CO. (2012, February 14). In Acronym Geek. Retrieved 01:11, February 14, 2012, from http://www.acronymgeek.com/CO |
| MLA | "CO." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/CO>. |
| MHRA | 'CO', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/CO> [accessed 14 February 2012] |
| Chicago | "CO", http://www.acronymgeek.com/CO (accessed February 14, 2012). |
| CBE/CSE | CO [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/CO. |
| Bluebook | CO, http://www.acronymgeek.com/CO (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, CO, http://www.acronymgeek.com/CO (optional description here) (as of Feb. 14, 2012, 01:11). |
| AMA | CO. Acronym Geek. February 14, 2012, 01:11. Available at: http://www.acronymgeek.com/CO. Accessed February 14, 2012, 01:11. |