| APA | ES. (2012, February 4). In Acronym Geek. Retrieved 11:44, February 4, 2012, from http://www.acronymgeek.com/ES |
| MLA | "ES." Acronym Geek. (2012). Acronym Geek. 4 Feb 2012 <http://www.acronymgeek.com/ES>. |
| MHRA | 'ES', Acronym Geek, 4 February 2012, <http://www.acronymgeek.com/ES> [accessed 4 February 2012] |
| Chicago | "ES", http://www.acronymgeek.com/ES (accessed February 4, 2012). |
| CBE/CSE | ES [Internet]. Acronym Geek; 2012 Feb 4 [cited 2012 Feb 4]. Available from: http://www.acronymgeek.com/ES. |
| Bluebook | ES, http://www.acronymgeek.com/ES (last visited February 4, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, ES, http://www.acronymgeek.com/ES (optional description here) (as of Feb. 4, 2012, 11:44). |
| AMA | ES. Acronym Geek. February 4, 2012, 11:44. Available at: http://www.acronymgeek.com/ES. Accessed February 4, 2012, 11:44. |