Mohd. Khairul bin Abu Sufi. (2017). Mapping the IIUM students' English language writing proficiency to the common European framework of reference for languages (CEFR). Kulliyyah of Islamic Revealed Knowldge and Human Sciences, International Islamic University Malaysia.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Mohd. Khairul bin Abu Sufi. Mapping the IIUM Students' English Language Writing Proficiency to the Common European Framework of Reference for Languages (CEFR). Gombak, Selangor: Kulliyyah of Islamic Revealed Knowldge and Human Sciences, International Islamic University Malaysia, 2017.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Mohd. Khairul bin Abu Sufi. Mapping the IIUM Students' English Language Writing Proficiency to the Common European Framework of Reference for Languages (CEFR). Kulliyyah of Islamic Revealed Knowldge and Human Sciences, International Islamic University Malaysia, 2017.