| APA | HIOS. (2012, February 17). In Acronym Geek. Retrieved 01:20, February 17, 2012, from http://www.acronymgeek.com/HIOS |
| MLA | "HIOS." Acronym Geek. (2012). Acronym Geek. 17 Feb 2012 <http://www.acronymgeek.com/HIOS>. |
| MHRA | 'HIOS', Acronym Geek, 17 February 2012, <http://www.acronymgeek.com/HIOS> [accessed 17 February 2012] |
| Chicago | "HIOS", http://www.acronymgeek.com/HIOS (accessed February 17, 2012). |
| CBE/CSE | HIOS [Internet]. Acronym Geek; 2012 Feb 17 [cited 2012 Feb 17]. Available from: http://www.acronymgeek.com/HIOS. |
| Bluebook | HIOS, http://www.acronymgeek.com/HIOS (last visited February 17, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HIOS, http://www.acronymgeek.com/HIOS (optional description here) (as of Feb. 17, 2012, 01:20). |
| AMA | HIOS. Acronym Geek. February 17, 2012, 01:20. Available at: http://www.acronymgeek.com/HIOS. Accessed February 17, 2012, 01:20. |