| APA | NUL. (2012, February 9). In Acronym Geek. Retrieved 19:59, February 9, 2012, from http://www.acronymgeek.com/NUL |
| MLA | "NUL." Acronym Geek. (2012). Acronym Geek. 9 Feb 2012 <http://www.acronymgeek.com/NUL>. |
| MHRA | 'NUL', Acronym Geek, 9 February 2012, <http://www.acronymgeek.com/NUL> [accessed 9 February 2012] |
| Chicago | "NUL", http://www.acronymgeek.com/NUL (accessed February 9, 2012). |
| CBE/CSE | NUL [Internet]. Acronym Geek; 2012 Feb 9 [cited 2012 Feb 9]. Available from: http://www.acronymgeek.com/NUL. |
| Bluebook | NUL, http://www.acronymgeek.com/NUL (last visited February 9, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, NUL, http://www.acronymgeek.com/NUL (optional description here) (as of Feb. 9, 2012, 19:59). |
| AMA | NUL. Acronym Geek. February 9, 2012, 19:59. Available at: http://www.acronymgeek.com/NUL. Accessed February 9, 2012, 19:59. |