| APA | ESI. (2012, February 14). In Acronym Geek. Retrieved 19:14, February 14, 2012, from http://www.acronymgeek.com/ESI |
| MLA | "ESI." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/ESI>. |
| MHRA | 'ESI', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/ESI> [accessed 14 February 2012] |
| Chicago | "ESI", http://www.acronymgeek.com/ESI (accessed February 14, 2012). |
| CBE/CSE | ESI [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/ESI. |
| Bluebook | ESI, http://www.acronymgeek.com/ESI (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, ESI, http://www.acronymgeek.com/ESI (optional description here) (as of Feb. 14, 2012, 19:14). |
| AMA | ESI. Acronym Geek. February 14, 2012, 19:14. Available at: http://www.acronymgeek.com/ESI. Accessed February 14, 2012, 19:14. |