Gaya APA

Lougheed, L. (2008). IELTS ( International English Language Testing System ) (C.1). Kassel: Binarupa Aksara Media.

Gaya MLA

Lougheed, Lin. "IELTS ( International English Language Testing System )". C.1 Kassel: Binarupa Aksara Media, 2008. Buku Teks.