Symposium on the Future as an Academic Discipline London, England, & ebrary, Inc. (1975). The future as an academic discipline. Elsevier/Excerpta Medica/North-Holland ; American Elsevier.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Symposium on the Future as an Academic Discipline London, England, و Inc ebrary. The Future as an Academic Discipline. Amsterdam : New York: Elsevier/Excerpta Medica/North-Holland ; American Elsevier, 1975.
توثيق جمعية اللغة المعاصرة MLA (الإصدار التاسع)Symposium on the Future as an Academic Discipline London, England, و Inc ebrary. The Future as an Academic Discipline. Elsevier/Excerpta Medica/North-Holland ; American Elsevier, 1975.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.