APA (7th ed.) Citation

Urban, T., Schmidt, H., & Weizsäcker, R. v. (2009). Polen. Beck.

Chicago Style (17th ed.) Citation

Urban, Thomas, Helmut Schmidt, and Richard von Weizsäcker. Polen. München: Beck, 2009.

MLA (8th ed.) Citation

Urban, Thomas, et al. Polen. Beck, 2009.