| APA | IEO. (2012, February 14). In Acronym Geek. Retrieved 09:55, February 14, 2012, from http://www.acronymgeek.com/IEO |
| MLA | "IEO." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/IEO>. |
| MHRA | 'IEO', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/IEO> [accessed 14 February 2012] |
| Chicago | "IEO", http://www.acronymgeek.com/IEO (accessed February 14, 2012). |
| CBE/CSE | IEO [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/IEO. |
| Bluebook | IEO, http://www.acronymgeek.com/IEO (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, IEO, http://www.acronymgeek.com/IEO (optional description here) (as of Feb. 14, 2012, 09:55). |
| AMA | IEO. Acronym Geek. February 14, 2012, 09:55. Available at: http://www.acronymgeek.com/IEO. Accessed February 14, 2012, 09:55. |