Guidelines for the Approval of Guest Students at German Universities issued by the Reich Ministry of Education [Germany]: “Article 1 – 2. Jews […] who are of German nationality, cannot be admitted as guest students at German universities any longer. […] Berlin 9 June 1938- The Reich Minister for Science, Training and People’s Education, signed by Zschinzsch”
Deutsche Wissenschaft, Erziehung und Volksbildung – 4.1938, page 294. Accessed online; Translated by Franziska Wagener 2/2/2015