| APA | DUO. (2012, February 14). In Acronym Geek. Retrieved 09:51, February 14, 2012, from http://www.acronymgeek.com/DUO |
| MLA | "DUO." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/DUO>. |
| MHRA | 'DUO', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/DUO> [accessed 14 February 2012] |
| Chicago | "DUO", http://www.acronymgeek.com/DUO (accessed February 14, 2012). |
| CBE/CSE | DUO [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/DUO. |
| Bluebook | DUO, http://www.acronymgeek.com/DUO (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, DUO, http://www.acronymgeek.com/DUO (optional description here) (as of Feb. 14, 2012, 09:51). |
| AMA | DUO. Acronym Geek. February 14, 2012, 09:51. Available at: http://www.acronymgeek.com/DUO. Accessed February 14, 2012, 09:51. |