| APA | HDY. (2012, February 13). In Acronym Geek. Retrieved 23:55, February 13, 2012, from http://www.acronymgeek.com/HDY |
| MLA | "HDY." Acronym Geek. (2012). Acronym Geek. 13 Feb 2012 <http://www.acronymgeek.com/HDY>. |
| MHRA | 'HDY', Acronym Geek, 13 February 2012, <http://www.acronymgeek.com/HDY> [accessed 13 February 2012] |
| Chicago | "HDY", http://www.acronymgeek.com/HDY (accessed February 13, 2012). |
| CBE/CSE | HDY [Internet]. Acronym Geek; 2012 Feb 13 [cited 2012 Feb 13]. Available from: http://www.acronymgeek.com/HDY. |
| Bluebook | HDY, http://www.acronymgeek.com/HDY (last visited February 13, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, HDY, http://www.acronymgeek.com/HDY (optional description here) (as of Feb. 13, 2012, 23:55). |
| AMA | HDY. Acronym Geek. February 13, 2012, 23:55. Available at: http://www.acronymgeek.com/HDY. Accessed February 13, 2012, 23:55. |