Seminar on UDC in a Mechanized Retrieval System Frankfurt, Germany, Freeman, R. R., Mølgaard-Hansen, R., & Westring-Nielsen, M. (1971). Proceedings of second seminar on UDC and mechanized information systems. Danish Centre for Documentation.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Seminar on UDC in a Mechanized Retrieval System Frankfurt, Germany, Robert R. Freeman, R. Mølgaard-Hansen, و Margit Westring-Nielsen. Proceedings of Second Seminar on UDC and Mechanized Information Systems. Copenhagen: Danish Centre for Documentation, 1971.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Seminar on UDC in a Mechanized Retrieval System Frankfurt, Germany, et al. Proceedings of Second Seminar on UDC and Mechanized Information Systems. Danish Centre for Documentation, 1971.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.