Não informado. University of Iowa studies in education. University of Iowa, College of Education.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Não informado. University of Iowa Studies in Education. Iowa City, Iowa: University of Iowa, College of Education.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Não informado. University of Iowa Studies in Education. University of Iowa, College of Education.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.