| APA | HHDI. (2012, February 16). In Acronym Geek. Retrieved 04:18, February 16, 2012, from http://www.acronymgeek.com/HHDI |
| MLA | "HHDI." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/HHDI>. |
| MHRA | 'HHDI', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/HHDI> [accessed 16 February 2012] |
| Chicago | "HHDI", http://www.acronymgeek.com/HHDI (accessed February 16, 2012). |
| CBE/CSE | HHDI [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/HHDI. |
| Bluebook | HHDI, http://www.acronymgeek.com/HHDI (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HHDI, http://www.acronymgeek.com/HHDI (optional description here) (as of Feb. 16, 2012, 04:18). |
| AMA | HHDI. Acronym Geek. February 16, 2012, 04:18. Available at: http://www.acronymgeek.com/HHDI. Accessed February 16, 2012, 04:18. |