| APA | NPDI. (2012, February 15). In Acronym Geek. Retrieved 08:38, February 15, 2012, from http://www.acronymgeek.com/NPDI |
| MLA | "NPDI." Acronym Geek. (2012). Acronym Geek. 15 Feb 2012 <http://www.acronymgeek.com/NPDI>. |
| MHRA | 'NPDI', Acronym Geek, 15 February 2012, <http://www.acronymgeek.com/NPDI> [accessed 15 February 2012] |
| Chicago | "NPDI", http://www.acronymgeek.com/NPDI (accessed February 15, 2012). |
| CBE/CSE | NPDI [Internet]. Acronym Geek; 2012 Feb 15 [cited 2012 Feb 15]. Available from: http://www.acronymgeek.com/NPDI. |
| Bluebook | NPDI, http://www.acronymgeek.com/NPDI (last visited February 15, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, NPDI, http://www.acronymgeek.com/NPDI (optional description here) (as of Feb. 15, 2012, 08:38). |
| AMA | NPDI. Acronym Geek. February 15, 2012, 08:38. Available at: http://www.acronymgeek.com/NPDI. Accessed February 15, 2012, 08:38. |