| APA | HBOA. (2012, February 11). In Acronym Geek. Retrieved 20:10, February 11, 2012, from http://www.acronymgeek.com/HBOA |
| MLA | "HBOA." Acronym Geek. (2012). Acronym Geek. 11 Feb 2012 <http://www.acronymgeek.com/HBOA>. |
| MHRA | 'HBOA', Acronym Geek, 11 February 2012, <http://www.acronymgeek.com/HBOA> [accessed 11 February 2012] |
| Chicago | "HBOA", http://www.acronymgeek.com/HBOA (accessed February 11, 2012). |
| CBE/CSE | HBOA [Internet]. Acronym Geek; 2012 Feb 11 [cited 2012 Feb 11]. Available from: http://www.acronymgeek.com/HBOA. |
| Bluebook | HBOA, http://www.acronymgeek.com/HBOA (last visited February 11, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HBOA, http://www.acronymgeek.com/HBOA (optional description here) (as of Feb. 11, 2012, 20:10). |
| AMA | HBOA. Acronym Geek. February 11, 2012, 20:10. Available at: http://www.acronymgeek.com/HBOA. Accessed February 11, 2012, 20:10. |