| APA | 420. (2012, February 11). In Acronym Geek. Retrieved 22:38, February 11, 2012, from http://www.acronymgeek.com/420 |
| MLA | "420." Acronym Geek. (2012). Acronym Geek. 11 Feb 2012 <http://www.acronymgeek.com/420>. |
| MHRA | '420', Acronym Geek, 11 February 2012, <http://www.acronymgeek.com/420> [accessed 11 February 2012] |
| Chicago | "420", http://www.acronymgeek.com/420 (accessed February 11, 2012). |
| CBE/CSE | 420 [Internet]. Acronym Geek; 2012 Feb 11 [cited 2012 Feb 11]. Available from: http://www.acronymgeek.com/420. |
| Bluebook | 420, http://www.acronymgeek.com/420 (last visited February 11, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, 420, http://www.acronymgeek.com/420 (optional description here) (as of Feb. 11, 2012, 22:38). |
| AMA | 420. Acronym Geek. February 11, 2012, 22:38. Available at: http://www.acronymgeek.com/420. Accessed February 11, 2012, 22:38. |