APA (7th ed.) Citation

Marx, K., & Engels, F. (1940). The civil war in the United States.

Chicago Style (17th ed.) Citation

Marx, Karl, and Friedrich Engels. The Civil War in the United States. 1940.

MLA (8th ed.) Citation

Marx, Karl, and Friedrich Engels. The Civil War in the United States. 1940.

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