Gaya APA

Black, M., Sharp, W. (2006). OBJECTIVE IELTS : self-study Student's Book Intermedia (SSB/intermediate). United Kingdom: Cambridge University Press.

Gaya MLA

Black, Michael., Sharp, Wendy. "OBJECTIVE IELTS : self-study Student's Book Intermedia". SSB/intermediate United Kingdom: Cambridge University Press, 2006. Text.