| APA | DDO. (2012, February 15). In Acronym Geek. Retrieved 03:28, February 15, 2012, from http://www.acronymgeek.com/DDO |
| MLA | "DDO." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/DDO>. |
| MHRA | 'DDO', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/DDO> [accessed 15 February 2012] |
| Chicago | "DDO", http://www.acronymgeek.com/DDO (accessed February 15, 2012). |
| CBE/CSE | DDO [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/DDO. |
| Bluebook | DDO, http://www.acronymgeek.com/DDO (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, DDO, http://www.acronymgeek.com/DDO (optional description here) (as of Feb. 15, 2012, 03:28). |
| AMA | DDO. Acronym Geek. February 15, 2012, 03:28. Available at: http://www.acronymgeek.com/DDO. Accessed February 15, 2012, 03:28. |