| APA | 4-PPY. (2012, February 12). In Acronym Geek. Retrieved 12:09, February 12, 2012, from http://www.acronymgeek.com/4-PPY |
| MLA | "4-PPY." Acronym Geek. (2012). Acronym Geek. 12 Feb 2012 <http://www.acronymgeek.com/4-PPY>. |
| MHRA | '4-PPY', Acronym Geek, 12 February 2012, <http://www.acronymgeek.com/4-PPY> [accessed 12 February 2012] |
| Chicago | "4-PPY", http://www.acronymgeek.com/4-PPY (accessed February 12, 2012). |
| CBE/CSE | 4-PPY [Internet]. Acronym Geek; 2012 Feb 12 [cited 2012 Feb 12]. Available from: http://www.acronymgeek.com/4-PPY. |
| Bluebook | 4-PPY, http://www.acronymgeek.com/4-PPY (last visited February 12, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, 4-PPY, http://www.acronymgeek.com/4-PPY (optional description here) (as of Feb. 12, 2012, 12:09). |
| AMA | 4-PPY. Acronym Geek. February 12, 2012, 12:09. Available at: http://www.acronymgeek.com/4-PPY. Accessed February 12, 2012, 12:09. |