Found in articles
istorijskih novina. Flechtheim, Ossip K. (1948). Die KPD in der Weimarer Republik. Offenbach. стр. 39—41. ISBN. Flechtheim, Ossip K. (1948). Die KPD in
Politische Schriften (Political Writings), edited and with preface by Ossip K. Flechtheim, 3 volumes, Frankfurt am Main, 1966 ff. The Complete Works of Rosa