| APA | R4X. (2012, February 13). In Acronym Geek. Retrieved 21:00, February 13, 2012, from http://www.acronymgeek.com/R4X |
| MLA | "R4X." Acronym Geek. (2012). Acronym Geek. 13 Feb 2012 <http://www.acronymgeek.com/R4X>. |
| MHRA | 'R4X', Acronym Geek, 13 February 2012, <http://www.acronymgeek.com/R4X> [accessed 13 February 2012] |
| Chicago | "R4X", http://www.acronymgeek.com/R4X (accessed February 13, 2012). |
| CBE/CSE | R4X [Internet]. Acronym Geek; 2012 Feb 13 [cited 2012 Feb 13]. Available from: http://www.acronymgeek.com/R4X. |
| Bluebook | R4X, http://www.acronymgeek.com/R4X (last visited February 13, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, R4X, http://www.acronymgeek.com/R4X (optional description here) (as of Feb. 13, 2012, 21:00). |
| AMA | R4X. Acronym Geek. February 13, 2012, 21:00. Available at: http://www.acronymgeek.com/R4X. Accessed February 13, 2012, 21:00. |