Zainil. (1987). A study of the spoken English proficiency of students in the SI program of the English department at the Padang Institute of Teacher Training and Education, Sumatra Barat, Indonesia. State University of New York.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Zainil. A Study of the Spoken English Proficiency of Students in the SI Program of the English Department at the Padang Institute of Teacher Training and Education, Sumatra Barat, Indonesia. Buffalo: State University of New York, 1987.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Zainil. A Study of the Spoken English Proficiency of Students in the SI Program of the English Department at the Padang Institute of Teacher Training and Education, Sumatra Barat, Indonesia. State University of New York, 1987.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.