APA (7th ed.) Citation

Sommer, W., & Zimmermann, R. (1945). Deutsche Sprachlehre. Worlds Alliance.

Chicago Style (17th ed.) Citation

Sommer, W., and Robert Zimmermann. Deutsche Sprachlehre. London: Worlds Alliance, 1945.

MLA (9th ed.) Citation

Sommer, W., and Robert Zimmermann. Deutsche Sprachlehre. Worlds Alliance, 1945.

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