| APA | ETR. (2012, February 14). In Acronym Geek. Retrieved 06:58, February 14, 2012, from http://www.acronymgeek.com/ETR |
| MLA | "ETR." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/ETR>. |
| MHRA | 'ETR', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/ETR> [accessed 14 February 2012] |
| Chicago | "ETR", http://www.acronymgeek.com/ETR (accessed February 14, 2012). |
| CBE/CSE | ETR [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/ETR. |
| Bluebook | ETR, http://www.acronymgeek.com/ETR (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, ETR, http://www.acronymgeek.com/ETR (optional description here) (as of Feb. 14, 2012, 06:58). |
| AMA | ETR. Acronym Geek. February 14, 2012, 06:58. Available at: http://www.acronymgeek.com/ETR. Accessed February 14, 2012, 06:58. |