| APA | HO. (2012, February 14). In Acronym Geek. Retrieved 06:53, February 14, 2012, from http://www.acronymgeek.com/HO |
| MLA | "HO." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/HO>. |
| MHRA | 'HO', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/HO> [accessed 14 February 2012] |
| Chicago | "HO", http://www.acronymgeek.com/HO (accessed February 14, 2012). |
| CBE/CSE | HO [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/HO. |
| Bluebook | HO, http://www.acronymgeek.com/HO (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HO, http://www.acronymgeek.com/HO (optional description here) (as of Feb. 14, 2012, 06:53). |
| AMA | HO. Acronym Geek. February 14, 2012, 06:53. Available at: http://www.acronymgeek.com/HO. Accessed February 14, 2012, 06:53. |