| APA | OTPO. (2012, February 17). In Acronym Geek. Retrieved 01:58, February 17, 2012, from http://www.acronymgeek.com/OTPO |
| MLA | "OTPO." Acronym Geek. (2012). Acronym Geek. 17 Feb 2012 <http://www.acronymgeek.com/OTPO>. |
| MHRA | 'OTPO', Acronym Geek, 17 February 2012, <http://www.acronymgeek.com/OTPO> [accessed 17 February 2012] |
| Chicago | "OTPO", http://www.acronymgeek.com/OTPO (accessed February 17, 2012). |
| CBE/CSE | OTPO [Internet]. Acronym Geek; 2012 Feb 17 [cited 2012 Feb 17]. Available from: http://www.acronymgeek.com/OTPO. |
| Bluebook | OTPO, http://www.acronymgeek.com/OTPO (last visited February 17, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OTPO, http://www.acronymgeek.com/OTPO (optional description here) (as of Feb. 17, 2012, 01:58). |
| AMA | OTPO. Acronym Geek. February 17, 2012, 01:58. Available at: http://www.acronymgeek.com/OTPO. Accessed February 17, 2012, 01:58. |