| APA | ESYS. (2012, February 16). In Acronym Geek. Retrieved 02:07, February 16, 2012, from http://www.acronymgeek.com/ESYS |
| MLA | "ESYS." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/ESYS>. |
| MHRA | 'ESYS', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/ESYS> [accessed 16 February 2012] |
| Chicago | "ESYS", http://www.acronymgeek.com/ESYS (accessed February 16, 2012). |
| CBE/CSE | ESYS [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/ESYS. |
| Bluebook | ESYS, http://www.acronymgeek.com/ESYS (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, ESYS, http://www.acronymgeek.com/ESYS (optional description here) (as of Feb. 16, 2012, 02:07). |
| AMA | ESYS. Acronym Geek. February 16, 2012, 02:07. Available at: http://www.acronymgeek.com/ESYS. Accessed February 16, 2012, 02:07. |