APA (7th ed.) Citation

Schönfeldt, H. c. 2. J., & Zühlsdorff, K. Commercial English. Winkler.

Chicago Style (17th ed.) Citation

Schönfeldt, Hellmut ca. 20. Jh, and Karl-Heinz Zühlsdorff. Commercial English. Darmstadt: Winkler.

MLA (9th ed.) Citation

Schönfeldt, Hellmut ca. 20. Jh, and Karl-Heinz Zühlsdorff. Commercial English. Winkler.