| APA | OPTU. (2012, February 16). In Acronym Geek. Retrieved 06:15, February 16, 2012, from http://www.acronymgeek.com/OPTU |
| MLA | "OPTU." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/OPTU>. |
| MHRA | 'OPTU', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/OPTU> [accessed 16 February 2012] |
| Chicago | "OPTU", http://www.acronymgeek.com/OPTU (accessed February 16, 2012). |
| CBE/CSE | OPTU [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/OPTU. |
| Bluebook | OPTU, http://www.acronymgeek.com/OPTU (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OPTU, http://www.acronymgeek.com/OPTU (optional description here) (as of Feb. 16, 2012, 06:15). |
| AMA | OPTU. Acronym Geek. February 16, 2012, 06:15. Available at: http://www.acronymgeek.com/OPTU. Accessed February 16, 2012, 06:15. |