Hewings, M. (1999). Advanced grammar in use: A self-study reference and practice book for advanced learners of English: with answers. Cambridge University.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Hewings, Martin. Advanced Grammar in Use: A Self-study Reference and Practice Book for Advanced Learners of English: With Answers. Nueva York: Cambridge University, 1999.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Hewings, Martin. Advanced Grammar in Use: A Self-study Reference and Practice Book for Advanced Learners of English: With Answers. Cambridge University, 1999.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.