| APA | ESOI. (2012, February 16). In Acronym Geek. Retrieved 22:00, February 16, 2012, from http://www.acronymgeek.com/ESOI |
| MLA | "ESOI." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/ESOI>. |
| MHRA | 'ESOI', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/ESOI> [accessed 16 February 2012] |
| Chicago | "ESOI", http://www.acronymgeek.com/ESOI (accessed February 16, 2012). |
| CBE/CSE | ESOI [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/ESOI. |
| Bluebook | ESOI, http://www.acronymgeek.com/ESOI (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, ESOI, http://www.acronymgeek.com/ESOI (optional description here) (as of Feb. 16, 2012, 22:00). |
| AMA | ESOI. Acronym Geek. February 16, 2012, 22:00. Available at: http://www.acronymgeek.com/ESOI. Accessed February 16, 2012, 22:00. |