| APA | XO. (2012, February 9). In Acronym Geek. Retrieved 00:45, February 9, 2012, from http://www.acronymgeek.com/XO |
| MLA | "XO." Acronym Geek. (2012). Acronym Geek. 9 Feb 2012 <http://www.acronymgeek.com/XO>. |
| MHRA | 'XO', Acronym Geek, 9 February 2012, <http://www.acronymgeek.com/XO> [accessed 9 February 2012] |
| Chicago | "XO", http://www.acronymgeek.com/XO (accessed February 9, 2012). |
| CBE/CSE | XO [Internet]. Acronym Geek; 2012 Feb 9 [cited 2012 Feb 9]. Available from: http://www.acronymgeek.com/XO. |
| Bluebook | XO, http://www.acronymgeek.com/XO (last visited February 9, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, XO, http://www.acronymgeek.com/XO (optional description here) (as of Feb. 9, 2012, 00:45). |
| AMA | XO. Acronym Geek. February 9, 2012, 00:45. Available at: http://www.acronymgeek.com/XO. Accessed February 9, 2012, 00:45. |