| APA | HTOS. (2012, February 11). In Acronym Geek. Retrieved 19:58, February 11, 2012, from http://www.acronymgeek.com/HTOS |
| MLA | "HTOS." Acronym Geek. (2012). Acronym Geek. 11 Feb 2012 <http://www.acronymgeek.com/HTOS>. |
| MHRA | 'HTOS', Acronym Geek, 11 February 2012, <http://www.acronymgeek.com/HTOS> [accessed 11 February 2012] |
| Chicago | "HTOS", http://www.acronymgeek.com/HTOS (accessed February 11, 2012). |
| CBE/CSE | HTOS [Internet]. Acronym Geek; 2012 Feb 11 [cited 2012 Feb 11]. Available from: http://www.acronymgeek.com/HTOS. |
| Bluebook | HTOS, http://www.acronymgeek.com/HTOS (last visited February 11, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HTOS, http://www.acronymgeek.com/HTOS (optional description here) (as of Feb. 11, 2012, 19:58). |
| AMA | HTOS. Acronym Geek. February 11, 2012, 19:58. Available at: http://www.acronymgeek.com/HTOS. Accessed February 11, 2012, 19:58. |