Gaya APA

Hidayati, N, N., Rizka, H. (2015). IELTS Preparation Lets Get the Highest Score for IELTS . yogjakarta: BALAI PUSTAKA.

Gaya MLA

Hidayati, Niswatin, Nurul., Rizka, Haira. "IELTS Preparation Lets Get the Highest Score for IELTS". yogjakarta: BALAI PUSTAKA, 2015. Text.