| APA | PTHO. (2012, February 16). In Acronym Geek. Retrieved 21:21, February 16, 2012, from http://www.acronymgeek.com/PTHO |
| MLA | "PTHO." Acronym Geek. (2012). Acronym Geek. 16 Feb 2012 <http://www.acronymgeek.com/PTHO>. |
| MHRA | 'PTHO', Acronym Geek, 16 February 2012, <http://www.acronymgeek.com/PTHO> [accessed 16 February 2012] |
| Chicago | "PTHO", http://www.acronymgeek.com/PTHO (accessed February 16, 2012). |
| CBE/CSE | PTHO [Internet]. Acronym Geek; 2012 Feb 16 [cited 2012 Feb 16]. Available from: http://www.acronymgeek.com/PTHO. |
| Bluebook | PTHO, http://www.acronymgeek.com/PTHO (last visited February 16, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PTHO, http://www.acronymgeek.com/PTHO (optional description here) (as of Feb. 16, 2012, 21:21). |
| AMA | PTHO. Acronym Geek. February 16, 2012, 21:21. Available at: http://www.acronymgeek.com/PTHO. Accessed February 16, 2012, 21:21. |