| APA | CO2. (2012, February 11). In Acronym Geek. Retrieved 22:40, February 11, 2012, from http://www.acronymgeek.com/CO2 |
| MLA | "CO2." Acronym Geek. (2012). Acronym Geek. 11 Feb 2012 <http://www.acronymgeek.com/CO2>. |
| MHRA | 'CO2', Acronym Geek, 11 February 2012, <http://www.acronymgeek.com/CO2> [accessed 11 February 2012] |
| Chicago | "CO2", http://www.acronymgeek.com/CO2 (accessed February 11, 2012). |
| CBE/CSE | CO2 [Internet]. Acronym Geek; 2012 Feb 11 [cited 2012 Feb 11]. Available from: http://www.acronymgeek.com/CO2. |
| Bluebook | CO2, http://www.acronymgeek.com/CO2 (last visited February 11, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, CO2, http://www.acronymgeek.com/CO2 (optional description here) (as of Feb. 11, 2012, 22:40). |
| AMA | CO2. Acronym Geek. February 11, 2012, 22:40. Available at: http://www.acronymgeek.com/CO2. Accessed February 11, 2012, 22:40. |