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.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Cullen, Pauline, Amanda French, و 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.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)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.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.