| APA | OPTR. (2012, February 15). In Acronym Geek. Retrieved 10:24, February 15, 2012, from http://www.acronymgeek.com/OPTR |
| MLA | "OPTR." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/OPTR>. |
| MHRA | 'OPTR', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/OPTR> [accessed 15 February 2012] |
| Chicago | "OPTR", http://www.acronymgeek.com/OPTR (accessed February 15, 2012). |
| CBE/CSE | OPTR [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/OPTR. |
| Bluebook | OPTR, http://www.acronymgeek.com/OPTR (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OPTR, http://www.acronymgeek.com/OPTR (optional description here) (as of Feb. 15, 2012, 10:24). |
| AMA | OPTR. Acronym Geek. February 15, 2012, 10:24. Available at: http://www.acronymgeek.com/OPTR. Accessed February 15, 2012, 10:24. |