| APA | CRK. (2012, February 14). In Acronym Geek. Retrieved 10:05, February 14, 2012, from http://www.acronymgeek.com/CRK |
| MLA | "CRK." Acronym Geek. (2012). Acronym Geek. 14 Feb 2012 <http://www.acronymgeek.com/CRK>. |
| MHRA | 'CRK', Acronym Geek, 14 February 2012, <http://www.acronymgeek.com/CRK> [accessed 14 February 2012] |
| Chicago | "CRK", http://www.acronymgeek.com/CRK (accessed February 14, 2012). |
| CBE/CSE | CRK [Internet]. Acronym Geek; 2012 Feb 14 [cited 2012 Feb 14]. Available from: http://www.acronymgeek.com/CRK. |
| Bluebook | CRK, http://www.acronymgeek.com/CRK (last visited February 14, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, CRK, http://www.acronymgeek.com/CRK (optional description here) (as of Feb. 14, 2012, 10:05). |
| AMA | CRK. Acronym Geek. February 14, 2012, 10:05. Available at: http://www.acronymgeek.com/CRK. Accessed February 14, 2012, 10:05. |