Al wasidi, A. A., & Al-Rajhi, A. (2007). Avoidance of perfect tenses: The case of beginner and intermediate saud learners of English. Al-Imam Muhammad ibn Saud Islamic University, College of Languages and Translation, Department of English.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Al wasidi, Amal A., و Ali Al-Rajhi. Avoidance of Perfect Tenses: The Case of Beginner and Intermediate Saud Learners of English. Riydh: Al-Imam Muhammad ibn Saud Islamic University, College of Languages and Translation, Department of English, 2007.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Al wasidi, Amal A., و Ali Al-Rajhi. Avoidance of Perfect Tenses: The Case of Beginner and Intermediate Saud Learners of English. Al-Imam Muhammad ibn Saud Islamic University, College of Languages and Translation, Department of English, 2007.