Johann Lehner (*1901) photographed with government troops on May 3, 1919, moments before they murdered him because they had mistaken him for a Bavarian Soviet Republic official.
Brown, Timothy S. (2009). Weimar Radicals: Nazis and Communists Between Authenticity and Performance. Berghahn.
Elsbach, Sebastian (2019). Das Reichsbanner Schwarz-Rot-Gold: Republikschutz und politische Gewalt in der Weimarer Republik [The Banner Black-Red-Gold: Republican defense and political violence in the Weimar Republic]. Franz Steiner Verlag. ISBN978-3515124676.
Jones, Mark (2018). Founding Weimar: Violence and the German Revolution of 1918–1919. Cambridge: Cambridge University Press. ISBN978-1107535527.
McDonough, Frank (2023). The Weimar Years: Rise and Fall 1918–1933. New York City: Apollo Publishers. ISBN978-1803284781.
Schumann, Dirk (2009). Political Violence in the Weimar Republic, 1918–1933: Fight for the Streets and Fear of Civil War. Berghahn.
Lindemann, Gerhard; Schmeitzner, Mike, eds. (2020). ...da schlagen wir zu: Politische Gewalt in Sachsen 1930–1935 [...there we strike: Political violence in Saxony 1930–1935]. Göttingen: V&R unipress. ISBN9783847109341.
Zerback, Ralf (2022). Triumph der Gewalt: Drei deutsche Jahre (1932 bis 1934) [Triumph of violence: Three German years (1932 to 1934)]. Stuttgart: Klett-Cotta. ISBN978-3608986488.