Friedenthal, R. (1981). Karl Marx. Piper.
Cita Chicago (17th ed.)Friedenthal, Richard. Karl Marx. München u.a.: Piper, 1981.
Cita MLA (8th ed.)Friedenthal, Richard. Karl Marx. Piper, 1981.
Atenció: Aquestes cites poden no estar 100% correctes.
Friedenthal, R. (1981). Karl Marx. Piper.
Cita Chicago (17th ed.)Friedenthal, Richard. Karl Marx. München u.a.: Piper, 1981.
Cita MLA (8th ed.)Friedenthal, Richard. Karl Marx. Piper, 1981.