APA (7th ed.) Citation

Engels, F., & Marx, K. (1954). Briefe über "Das Kapital".

Chicago Style (17th ed.) Citation

Engels, Friedrich, and Karl Marx. Briefe über "Das Kapital". 1954.

MLA (8th ed.) Citation

Engels, Friedrich, and Karl Marx. Briefe über "Das Kapital". 1954.

Warning: These citations may not always be 100% accurate.