| APA | OPFS. (2012, February 15). In Acronym Geek. Retrieved 04:20, February 15, 2012, from http://www.acronymgeek.com/OPFS |
| MLA | "OPFS." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/OPFS>. |
| MHRA | 'OPFS', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/OPFS> [accessed 15 February 2012] |
| Chicago | "OPFS", http://www.acronymgeek.com/OPFS (accessed February 15, 2012). |
| CBE/CSE | OPFS [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/OPFS. |
| Bluebook | OPFS, http://www.acronymgeek.com/OPFS (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, OPFS, http://www.acronymgeek.com/OPFS (optional description here) (as of Feb. 15, 2012, 04:20). |
| AMA | OPFS. Acronym Geek. February 15, 2012, 04:20. Available at: http://www.acronymgeek.com/OPFS. Accessed February 15, 2012, 04:20. |