| APA | HREO. (2012, February 17). In Acronym Geek. Retrieved 04:46, February 17, 2012, from http://www.acronymgeek.com/HREO |
| MLA | "HREO." Acronym Geek. (2012). Acronym Geek. 17 Feb 2012 <http://www.acronymgeek.com/HREO>. |
| MHRA | 'HREO', Acronym Geek, 17 February 2012, <http://www.acronymgeek.com/HREO> [accessed 17 February 2012] |
| Chicago | "HREO", http://www.acronymgeek.com/HREO (accessed February 17, 2012). |
| CBE/CSE | HREO [Internet]. Acronym Geek; 2012 Feb 17 [cited 2012 Feb 17]. Available from: http://www.acronymgeek.com/HREO. |
| Bluebook | HREO, http://www.acronymgeek.com/HREO (last visited February 17, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HREO, http://www.acronymgeek.com/HREO (optional description here) (as of Feb. 17, 2012, 04:46). |
| AMA | HREO. Acronym Geek. February 17, 2012, 04:46. Available at: http://www.acronymgeek.com/HREO. Accessed February 17, 2012, 04:46. |