| APA | HHEN. (2012, February 14). In Acronym Geek. Retrieved 23:46, February 14, 2012, from http://www.acronymgeek.com/HHEN |
| MLA | "HHEN." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/HHEN>. |
| MHRA | 'HHEN', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/HHEN> [accessed 14 February 2012] |
| Chicago | "HHEN", http://www.acronymgeek.com/HHEN (accessed February 14, 2012). |
| CBE/CSE | HHEN [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/HHEN. |
| Bluebook | HHEN, http://www.acronymgeek.com/HHEN (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HHEN, http://www.acronymgeek.com/HHEN (optional description here) (as of Feb. 14, 2012, 23:46). |
| AMA | HHEN. Acronym Geek. February 14, 2012, 23:46. Available at: http://www.acronymgeek.com/HHEN. Accessed February 14, 2012, 23:46. |