Herbert Linder: From the NSDAP to the SPD. The political life of Dr. Hemuth Klotz (1894–1943). (= Karlsruher Contributions to the History of National Socialism. Volume 3) Universitätsverlag Konstanz, Konstanz 1995, ISBN 3-87940-607-3, p. 174ff. Message in the Reichstag session by Reichstag President Paul Löbe, see Minutes of the Reichstag session of 12 May 1932
