| APA | PTHD. (2012, February 15). In Acronym Geek. Retrieved 16:59, February 15, 2012, from http://www.acronymgeek.com/PTHD |
| MLA | "PTHD." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/PTHD>. |
| MHRA | 'PTHD', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/PTHD> [accessed 15 February 2012] |
| Chicago | "PTHD", http://www.acronymgeek.com/PTHD (accessed February 15, 2012). |
| CBE/CSE | PTHD [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/PTHD. |
| Bluebook | PTHD, http://www.acronymgeek.com/PTHD (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PTHD, http://www.acronymgeek.com/PTHD (optional description here) (as of Feb. 15, 2012, 16:59). |
| AMA | PTHD. Acronym Geek. February 15, 2012, 16:59. Available at: http://www.acronymgeek.com/PTHD. Accessed February 15, 2012, 16:59. |