El-Hibir, B. I. (1976). Sources of common errors in the written English of Sudanese secondary school students. University of Wales.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)El-Hibir, Babiker Idris. Sources of Common Errors in the Written English of Sudanese Secondary School Students. Cardiff: University of Wales, 1976.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)El-Hibir, Babiker Idris. Sources of Common Errors in the Written English of Sudanese Secondary School Students. University of Wales, 1976.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.