Plötner, R. (1960). Wilhelm Pieck.
Cita Chicago (17th ed.)Plötner, Ruth. Wilhelm Pieck. Berlin, 1960.
Cita MLA (8th ed.)Plötner, Ruth. Wilhelm Pieck. 1960.
Atenció: Aquestes cites poden no estar 100% correctes.
Cita APA (7th ed.)