| APA | PENL. (2012, February 15). In Acronym Geek. Retrieved 05:30, February 15, 2012, from http://www.acronymgeek.com/PENL |
| MLA | "PENL." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/PENL>. |
| MHRA | 'PENL', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/PENL> [accessed 15 February 2012] |
| Chicago | "PENL", http://www.acronymgeek.com/PENL (accessed February 15, 2012). |
| CBE/CSE | PENL [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/PENL. |
| Bluebook | PENL, http://www.acronymgeek.com/PENL (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, PENL, http://www.acronymgeek.com/PENL (optional description here) (as of Feb. 15, 2012, 05:30). |
| AMA | PENL. Acronym Geek. February 15, 2012, 05:30. Available at: http://www.acronymgeek.com/PENL. Accessed February 15, 2012, 05:30. |