Gaya APA
IELTS : International English Language Testing System. (2016).
New York:
Barrons.
Gaya Chicago
IELTS : International English Language Testing System.
Edisi keempat.
New York:
Barrons,
2016.
Printed Book.
Gaya MLA
IELTS : International English Language Testing System.
Edisi keempat.
New York:
Barrons,
2016.
Printed Book.
Gaya Turabian
IELTS : International English Language Testing System.
New York:
Barrons,
2016.
Printed Book.