| APA | -O. (2012, February 10). In Acronym Geek. Retrieved 09:41, February 10, 2012, from http://www.acronymgeek.com/-O |
| MLA | "-O." Acronym Geek. (2012). Acronym Geek. 10 Feb 2012 <http://www.acronymgeek.com/-O>. |
| MHRA | '-O', Acronym Geek, 10 February 2012, <http://www.acronymgeek.com/-O> [accessed 10 February 2012] |
| Chicago | "-O", http://www.acronymgeek.com/-O (accessed February 10, 2012). |
| CBE/CSE | -O [Internet]. Acronym Geek; 2012 Feb 10 [cited 2012 Feb 10]. Available from: http://www.acronymgeek.com/-O. |
| Bluebook | -O, http://www.acronymgeek.com/-O (last visited February 10, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, -O, http://www.acronymgeek.com/-O (optional description here) (as of Feb. 10, 2012, 09:41). |
| AMA | -O. Acronym Geek. February 10, 2012, 09:41. Available at: http://www.acronymgeek.com/-O. Accessed February 10, 2012, 09:41. |