| APA | HHL. (2012, February 14). In Acronym Geek. Retrieved 04:25, February 14, 2012, from http://www.acronymgeek.com/HHL |
| MLA | "HHL." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/HHL>. |
| MHRA | 'HHL', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/HHL> [accessed 14 February 2012] |
| Chicago | "HHL", http://www.acronymgeek.com/HHL (accessed February 14, 2012). |
| CBE/CSE | HHL [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/HHL. |
| Bluebook | HHL, http://www.acronymgeek.com/HHL (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HHL, http://www.acronymgeek.com/HHL (optional description here) (as of Feb. 14, 2012, 04:25). |
| AMA | HHL. Acronym Geek. February 14, 2012, 04:25. Available at: http://www.acronymgeek.com/HHL. Accessed February 14, 2012, 04:25. |