| APA | HHEI. (2012, February 15). In Acronym Geek. Retrieved 19:12, February 15, 2012, from http://www.acronymgeek.com/HHEI |
| MLA | "HHEI." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/HHEI>. |
| MHRA | 'HHEI', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/HHEI> [accessed 15 February 2012] |
| Chicago | "HHEI", http://www.acronymgeek.com/HHEI (accessed February 15, 2012). |
| CBE/CSE | HHEI [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/HHEI. |
| Bluebook | HHEI, http://www.acronymgeek.com/HHEI (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HHEI, http://www.acronymgeek.com/HHEI (optional description here) (as of Feb. 15, 2012, 19:12). |
| AMA | HHEI. Acronym Geek. February 15, 2012, 19:12. Available at: http://www.acronymgeek.com/HHEI. Accessed February 15, 2012, 19:12. |