Urban, T., Schmidt, H., & Weizsäcker, R. v. (2009). Polen. Beck.
Chicago Style (17th ed.) CitationUrban, Thomas, Helmut Schmidt, and Richard von Weizsäcker. Polen. München: Beck, 2009.
MLA (8th ed.) CitationUrban, Thomas, et al. Polen. Beck, 2009.
Warning: These citations may not always be 100% accurate.