| APA | HHGK. (2012, February 15). In Acronym Geek. Retrieved 12:35, February 15, 2012, from http://www.acronymgeek.com/HHGK |
| MLA | "HHGK." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/HHGK>. |
| MHRA | 'HHGK', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/HHGK> [accessed 15 February 2012] |
| Chicago | "HHGK", http://www.acronymgeek.com/HHGK (accessed February 15, 2012). |
| CBE/CSE | HHGK [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/HHGK. |
| Bluebook | HHGK, http://www.acronymgeek.com/HHGK (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HHGK, http://www.acronymgeek.com/HHGK (optional description here) (as of Feb. 15, 2012, 12:35). |
| AMA | HHGK. Acronym Geek. February 15, 2012, 12:35. Available at: http://www.acronymgeek.com/HHGK. Accessed February 15, 2012, 12:35. |