APA (7th ed.) Citation

Ostermann, P., & Stöffler, N. O. Learning English, modern course. Ostermann.

Chicago Style (17th ed.) Citation

Ostermann, Peter, and Norbert O. Stöffler. Learning English, Modern Course. München: Ostermann.

MLA (9th ed.) Citation

Ostermann, Peter, and Norbert O. Stöffler. Learning English, Modern Course. Ostermann.

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