| APA | EO. (2012, February 9). In Acronym Geek. Retrieved 13:56, February 9, 2012, from http://www.acronymgeek.com/EO |
| MLA | "EO." Acronym Geek. (2012). Acronym Geek. 9 Feb 2012 <http://www.acronymgeek.com/EO>. |
| MHRA | 'EO', Acronym Geek, 9 February 2012, <http://www.acronymgeek.com/EO> [accessed 9 February 2012] |
| Chicago | "EO", http://www.acronymgeek.com/EO (accessed February 9, 2012). |
| CBE/CSE | EO [Internet]. Acronym Geek; 2012 Feb 9 [cited 2012 Feb 9]. Available from: http://www.acronymgeek.com/EO. |
| Bluebook | EO, http://www.acronymgeek.com/EO (last visited February 9, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, EO, http://www.acronymgeek.com/EO (optional description here) (as of Feb. 9, 2012, 13:56). |
| AMA | EO. Acronym Geek. February 9, 2012, 13:56. Available at: http://www.acronymgeek.com/EO. Accessed February 9, 2012, 13:56. |