APA

Black M., Sharp W., . (2006). Objective IELTS. Intermediate. : Cambridge University Press.

Chicago

Black M, Sharp W, . 2006. Objective IELTS. Intermediate. : Cambridge University Press.

Harvard

Black M., Sharp W., . (2006). Objective IELTS. Intermediate. : Cambridge University Press.

MLA

Black M, Sharp W, . Objective IELTS. Intermediate. : Cambridge University Press. 2006.