| APA | 4X. (2012, February 10). In Acronym Geek. Retrieved 10:37, February 10, 2012, from http://www.acronymgeek.com/4X |
| MLA | "4X." Acronym Geek. (2012). Acronym Geek. 10 Feb 2012 <http://www.acronymgeek.com/4X>. |
| MHRA | '4X', Acronym Geek, 10 February 2012, <http://www.acronymgeek.com/4X> [accessed 10 February 2012] |
| Chicago | "4X", http://www.acronymgeek.com/4X (accessed February 10, 2012). |
| CBE/CSE | 4X [Internet]. Acronym Geek; 2012 Feb 10 [cited 2012 Feb 10]. Available from: http://www.acronymgeek.com/4X. |
| Bluebook | 4X, http://www.acronymgeek.com/4X (last visited February 10, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, 4X, http://www.acronymgeek.com/4X (optional description here) (as of Feb. 10, 2012, 10:37). |
| AMA | 4X. Acronym Geek. February 10, 2012, 10:37. Available at: http://www.acronymgeek.com/4X. Accessed February 10, 2012, 10:37. |