| APA | QHO2. (2012, February 11). In Acronym Geek. Retrieved 21:22, February 11, 2012, from http://www.acronymgeek.com/QHO2 |
| MLA | "QHO2." Acronym Geek. (2012). Acronym Geek. 11 Feb 2012 <http://www.acronymgeek.com/QHO2>. |
| MHRA | 'QHO2', Acronym Geek, 11 February 2012, <http://www.acronymgeek.com/QHO2> [accessed 11 February 2012] |
| Chicago | "QHO2", http://www.acronymgeek.com/QHO2 (accessed February 11, 2012). |
| CBE/CSE | QHO2 [Internet]. Acronym Geek; 2012 Feb 11 [cited 2012 Feb 11]. Available from: http://www.acronymgeek.com/QHO2. |
| Bluebook | QHO2, http://www.acronymgeek.com/QHO2 (last visited February 11, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, QHO2, http://www.acronymgeek.com/QHO2 (optional description here) (as of Feb. 11, 2012, 21:22). |
| AMA | QHO2. Acronym Geek. February 11, 2012, 21:22. Available at: http://www.acronymgeek.com/QHO2. Accessed February 11, 2012, 21:22. |