Lüdtke, A. (2012). History of concepts, new edition: Suitable for a better understanding of modern times? / Alf Lüdtke. Contributions to the history of concepts.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Lüdtke, Alf. "History of Concepts, New Edition: Suitable for a Better Understanding of Modern Times? / Alf Lüdtke." Contributions to the History of Concepts 2012.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Lüdtke, Alf. "History of Concepts, New Edition: Suitable for a Better Understanding of Modern Times? / Alf Lüdtke." Contributions to the History of Concepts, 2012.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.