APA

Hopkins D., Cullen P., . (2007). Cambridge Grammar for IELTS. Cambridge: Cambridge University Press.

Chicago

Hopkins D, Cullen P, . 2007. Cambridge Grammar for IELTS. Cambridge: Cambridge University Press.

Harvard

Hopkins D., Cullen P., . (2007). Cambridge Grammar for IELTS. Cambridge: Cambridge University Press.

MLA

Hopkins D, Cullen P, . Cambridge Grammar for IELTS. Cambridge: Cambridge University Press. 2007.