Kahlen, L. (2005). Interactive German grammar made easy. McGraw-Hill.
Cita Chicago (17th ed.)Kahlen, Lisa. Interactive German Grammar Made Easy. New York: McGraw-Hill, 2005.
Cita MLA (9th ed.)Kahlen, Lisa. Interactive German Grammar Made Easy. McGraw-Hill, 2005.
Atenció: Aquestes cites poden no estar 100% correctes.