Roith, Christian (2011). La historia de la teoría crítica. Universidad de Almería. Departamento de Ciencias Humanas y Sociales. Área de Teoría e Historia de la Educación. pp. 9-10. Consultado el 4 de febrero de 2019.
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Löwenthal, Leo (1987). «The Institute of Social Research». En The Regents of the University of California, ed. An Unmastered Past. The Autobiographical Reflections of Leo Lowenthal(en inglés). Editado con una introducción de Martin Jay. Berkeley · Los Angeles · Oxford: University of California Press. p. 53. «The decision to emigrate, or rather to prepare to do so, took place on September 14, 1930, when 107 National Socialists entered the Reichstag. These elections were crucial. During the previous months we had not paid much attention to the general state of the world, for we were still celebrating our honeymoon at the Institute. However, during 1930–1931 it was becoming clear».
