| APA | NXXI. (2012, February 12). In Acronym Geek. Retrieved 12:47, February 12, 2012, from http://www.acronymgeek.com/NXXI |
| MLA | "NXXI." Acronym Geek. (2012). Acronym Geek. 12 Feb 2012 <http://www.acronymgeek.com/NXXI>. |
| MHRA | 'NXXI', Acronym Geek, 12 February 2012, <http://www.acronymgeek.com/NXXI> [accessed 12 February 2012] |
| Chicago | "NXXI", http://www.acronymgeek.com/NXXI (accessed February 12, 2012). |
| CBE/CSE | NXXI [Internet]. Acronym Geek; 2012 Feb 12 [cited 2012 Feb 12]. Available from: http://www.acronymgeek.com/NXXI. |
| Bluebook | NXXI, http://www.acronymgeek.com/NXXI (last visited February 12, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, NXXI, http://www.acronymgeek.com/NXXI (optional description here) (as of Feb. 12, 2012, 12:47). |
| AMA | NXXI. Acronym Geek. February 12, 2012, 12:47. Available at: http://www.acronymgeek.com/NXXI. Accessed February 12, 2012, 12:47. |