| APA | RA-221. (2012, February 12). In Acronym Geek. Retrieved 15:32, February 12, 2012, from http://www.acronymgeek.com/RA-221 |
| MLA | "RA-221." Acronym Geek. (2012). Acronym Geek. 12 Feb 2012 <http://www.acronymgeek.com/RA-221>. |
| MHRA | 'RA-221', Acronym Geek, 12 February 2012, <http://www.acronymgeek.com/RA-221> [accessed 12 February 2012] |
| Chicago | "RA-221", http://www.acronymgeek.com/RA-221 (accessed February 12, 2012). |
| CBE/CSE | RA-221 [Internet]. Acronym Geek; 2012 Feb 12 [cited 2012 Feb 12]. Available from: http://www.acronymgeek.com/RA-221. |
| Bluebook | RA-221, http://www.acronymgeek.com/RA-221 (last visited February 12, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, RA-221, http://www.acronymgeek.com/RA-221 (optional description here) (as of Feb. 12, 2012, 15:32). |
| AMA | RA-221. Acronym Geek. February 12, 2012, 15:32. Available at: http://www.acronymgeek.com/RA-221. Accessed February 12, 2012, 15:32. |