University of Chicago. Industrial Relations Center. (1967). Exchange: Elementary school economics III (Field test ed.). Industrial Relations Center, University of Chicago.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)University of Chicago. Industrial Relations Center. Exchange: Elementary School Economics III. Field test ed. Chicago: Industrial Relations Center, University of Chicago, 1967.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)University of Chicago. Industrial Relations Center. Exchange: Elementary School Economics III. Field test ed. Industrial Relations Center, University of Chicago, 1967.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.