| APA | PTBL. (2012, February 17). In Acronym Geek. Retrieved 00:11, February 17, 2012, from http://www.acronymgeek.com/PTBL |
| MLA | "PTBL." Acronym Geek. (2012). Acronym Geek. 17 Feb 2012 <http://www.acronymgeek.com/PTBL>. |
| MHRA | 'PTBL', Acronym Geek, 17 February 2012, <http://www.acronymgeek.com/PTBL> [accessed 17 February 2012] |
| Chicago | "PTBL", http://www.acronymgeek.com/PTBL (accessed February 17, 2012). |
| CBE/CSE | PTBL [Internet]. Acronym Geek; 2012 Feb 17 [cited 2012 Feb 17]. Available from: http://www.acronymgeek.com/PTBL. |
| Bluebook | PTBL, http://www.acronymgeek.com/PTBL (last visited February 17, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PTBL, http://www.acronymgeek.com/PTBL (optional description here) (as of Feb. 17, 2012, 00:11). |
| AMA | PTBL. Acronym Geek. February 17, 2012, 00:11. Available at: http://www.acronymgeek.com/PTBL. Accessed February 17, 2012, 00:11. |