(1955). Briefe. Eugen Diederichs.
Cita Chicago (17th ed.)Briefe. Düsseldorf: Eugen Diederichs, 1955.
Cita MLA (9th ed.)Briefe. Eugen Diederichs, 1955.
Atenció: Aquestes cites poden no estar 100% correctes.
Cita APA (7th ed.)