Cullen, P., French, A., & Jakeman, V. (2014). The official Cambridge guide to IELTS: For academic & general training : student's book with answers. Cambridge University Press : Cambridge English Language Assessment.
Παραπομπή σε μορφή Chicago (17η εκδ.)Cullen, Pauline, Amanda French, και Vanessa Jakeman. The Official Cambridge Guide to IELTS: For Academic & General Training : Student's Book with Answers. [Cambridge, England]: Cambridge University Press : Cambridge English Language Assessment, 2014.
Παραπομπή σε μορφή MLA (9th εκδ.)Cullen, Pauline, et al. The Official Cambridge Guide to IELTS: For Academic & General Training : Student's Book with Answers. Cambridge University Press : Cambridge English Language Assessment, 2014.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.