| APA | HBAO. (2012, February 12). In Acronym Geek. Retrieved 13:02, February 12, 2012, from http://www.acronymgeek.com/HBAO |
| MLA | "HBAO." Acronym Geek. (2012). Acronym Geek. 12 Feb 2012 <http://www.acronymgeek.com/HBAO>. |
| MHRA | 'HBAO', Acronym Geek, 12 February 2012, <http://www.acronymgeek.com/HBAO> [accessed 12 February 2012] |
| Chicago | "HBAO", http://www.acronymgeek.com/HBAO (accessed February 12, 2012). |
| CBE/CSE | HBAO [Internet]. Acronym Geek; 2012 Feb 12 [cited 2012 Feb 12]. Available from: http://www.acronymgeek.com/HBAO. |
| Bluebook | HBAO, http://www.acronymgeek.com/HBAO (last visited February 12, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HBAO, http://www.acronymgeek.com/HBAO (optional description here) (as of Feb. 12, 2012, 13:02). |
| AMA | HBAO. Acronym Geek. February 12, 2012, 13:02. Available at: http://www.acronymgeek.com/HBAO. Accessed February 12, 2012, 13:02. |