Karl Marx and the close of his system - Bohm - Bawerk, Eugen von, 1851-1914. (A. M. Kelley, 1973)
The work of E. Bθohm von Bawerk is a translation of Zum Abschluss des Marxschen Systems; the work by R. Hilferding, a translation of Bθohm-Bawerks Marx-Kritik.