| APA | PTBI. (2012, February 14). In Acronym Geek. Retrieved 18:45, February 14, 2012, from http://www.acronymgeek.com/PTBI |
| MLA | "PTBI." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/PTBI>. |
| MHRA | 'PTBI', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/PTBI> [accessed 14 February 2012] |
| Chicago | "PTBI", http://www.acronymgeek.com/PTBI (accessed February 14, 2012). |
| CBE/CSE | PTBI [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/PTBI. |
| Bluebook | PTBI, http://www.acronymgeek.com/PTBI (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PTBI, http://www.acronymgeek.com/PTBI (optional description here) (as of Feb. 14, 2012, 18:45). |
| AMA | PTBI. Acronym Geek. February 14, 2012, 18:45. Available at: http://www.acronymgeek.com/PTBI. Accessed February 14, 2012, 18:45. |