Black, M. (2006). Objective IELTS: Intermediate Workbook with Answers. Cambridge, UK: Cambridge University Press.
Παραπομπή Chicago StyleBlack, Michael. Objective IELTS: Intermediate Workbook With Answers. Cambridge, UK: Cambridge University Press, 2006.
Παραπομπή MLABlack, Michael. Objective IELTS: Intermediate Workbook With Answers. Cambridge, UK: Cambridge University Press, 2006.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.