| APA | HTLO. (2012, February 16). In Acronym Geek. Retrieved 22:53, February 16, 2012, from http://www.acronymgeek.com/HTLO |
| MLA | "HTLO." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/HTLO>. |
| MHRA | 'HTLO', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/HTLO> [accessed 16 February 2012] |
| Chicago | "HTLO", http://www.acronymgeek.com/HTLO (accessed February 16, 2012). |
| CBE/CSE | HTLO [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/HTLO. |
| Bluebook | HTLO, http://www.acronymgeek.com/HTLO (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HTLO, http://www.acronymgeek.com/HTLO (optional description here) (as of Feb. 16, 2012, 22:53). |
| AMA | HTLO. Acronym Geek. February 16, 2012, 22:53. Available at: http://www.acronymgeek.com/HTLO. Accessed February 16, 2012, 22:53. |