| APA | OPVA. (2012, February 15). In Acronym Geek. Retrieved 06:28, February 15, 2012, from http://www.acronymgeek.com/OPVA |
| MLA | "OPVA." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/OPVA>. |
| MHRA | 'OPVA', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/OPVA> [accessed 15 February 2012] |
| Chicago | "OPVA", http://www.acronymgeek.com/OPVA (accessed February 15, 2012). |
| CBE/CSE | OPVA [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/OPVA. |
| Bluebook | OPVA, http://www.acronymgeek.com/OPVA (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OPVA, http://www.acronymgeek.com/OPVA (optional description here) (as of Feb. 15, 2012, 06:28). |
| AMA | OPVA. Acronym Geek. February 15, 2012, 06:28. Available at: http://www.acronymgeek.com/OPVA. Accessed February 15, 2012, 06:28. |