| APA | 891. (2012, February 10). In Acronym Geek. Retrieved 09:41, February 10, 2012, from http://www.acronymgeek.com/891 |
| MLA | "891." Acronym Geek. (2012). Acronym Geek. 10 Feb 2012 <http://www.acronymgeek.com/891>. |
| MHRA | '891', Acronym Geek, 10 February 2012, <http://www.acronymgeek.com/891> [accessed 10 February 2012] |
| Chicago | "891", http://www.acronymgeek.com/891 (accessed February 10, 2012). |
| CBE/CSE | 891 [Internet]. Acronym Geek; 2012 Feb 10 [cited 2012 Feb 10]. Available from: http://www.acronymgeek.com/891. |
| Bluebook | 891, http://www.acronymgeek.com/891 (last visited February 10, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, 891, http://www.acronymgeek.com/891 (optional description here) (as of Feb. 10, 2012, 09:41). |
| AMA | 891. Acronym Geek. February 10, 2012, 09:41. Available at: http://www.acronymgeek.com/891. Accessed February 10, 2012, 09:41. |