| APA | GCGS. (2012, February 17). In Acronym Geek. Retrieved 08:00, February 17, 2012, from http://www.acronymgeek.com/GCGS |
| MLA | "GCGS." Acronym Geek. (2012). Acronym Geek. 17 Feb 2012 <http://www.acronymgeek.com/GCGS>. |
| MHRA | 'GCGS', Acronym Geek, 17 February 2012, <http://www.acronymgeek.com/GCGS> [accessed 17 February 2012] |
| Chicago | "GCGS", http://www.acronymgeek.com/GCGS (accessed February 17, 2012). |
| CBE/CSE | GCGS [Internet]. Acronym Geek; 2012 Feb 17 [cited 2012 Feb 17]. Available from: http://www.acronymgeek.com/GCGS. |
| Bluebook | GCGS, http://www.acronymgeek.com/GCGS (last visited February 17, 2012). |
| Bluebook: Harvard JOLT | See Acronym Geek, GCGS, http://www.acronymgeek.com/GCGS (optional description here) (as of Feb. 17, 2012, 08:00). |
| AMA | GCGS. Acronym Geek. February 17, 2012, 08:00. Available at: http://www.acronymgeek.com/GCGS. Accessed February 17, 2012, 08:00. |