| APA | OTPE. (2012, February 15). In Acronym Geek. Retrieved 12:25, February 15, 2012, from http://www.acronymgeek.com/OTPE |
| MLA | "OTPE." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/OTPE>. |
| MHRA | 'OTPE', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/OTPE> [accessed 15 February 2012] |
| Chicago | "OTPE", http://www.acronymgeek.com/OTPE (accessed February 15, 2012). |
| CBE/CSE | OTPE [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/OTPE. |
| Bluebook | OTPE, http://www.acronymgeek.com/OTPE (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OTPE, http://www.acronymgeek.com/OTPE (optional description here) (as of Feb. 15, 2012, 12:25). |
| AMA | OTPE. Acronym Geek. February 15, 2012, 12:25. Available at: http://www.acronymgeek.com/OTPE. Accessed February 15, 2012, 12:25. |