| APA | HFDO. (2012, February 17). In Acronym Geek. Retrieved 02:46, February 17, 2012, from http://www.acronymgeek.com/HFDO |
| MLA | "HFDO." Acronym Geek. (2012). Acronym Geek. 17 Feb 2012 <http://www.acronymgeek.com/HFDO>. |
| MHRA | 'HFDO', Acronym Geek, 17 February 2012, <http://www.acronymgeek.com/HFDO> [accessed 17 February 2012] |
| Chicago | "HFDO", http://www.acronymgeek.com/HFDO (accessed February 17, 2012). |
| CBE/CSE | HFDO [Internet]. Acronym Geek; 2012 Feb 17 [cited 2012 Feb 17]. Available from: http://www.acronymgeek.com/HFDO. |
| Bluebook | HFDO, http://www.acronymgeek.com/HFDO (last visited February 17, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HFDO, http://www.acronymgeek.com/HFDO (optional description here) (as of Feb. 17, 2012, 02:46). |
| AMA | HFDO. Acronym Geek. February 17, 2012, 02:46. Available at: http://www.acronymgeek.com/HFDO. Accessed February 17, 2012, 02:46. |