| APA | ESA. (2012, February 14). In Acronym Geek. Retrieved 19:18, February 14, 2012, from http://www.acronymgeek.com/ESA |
| MLA | "ESA." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/ESA>. |
| MHRA | 'ESA', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/ESA> [accessed 14 February 2012] |
| Chicago | "ESA", http://www.acronymgeek.com/ESA (accessed February 14, 2012). |
| CBE/CSE | ESA [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/ESA. |
| Bluebook | ESA, http://www.acronymgeek.com/ESA (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, ESA, http://www.acronymgeek.com/ESA (optional description here) (as of Feb. 14, 2012, 19:18). |
| AMA | ESA. Acronym Geek. February 14, 2012, 19:18. Available at: http://www.acronymgeek.com/ESA. Accessed February 14, 2012, 19:18. |