Original: For his paper Die Wesensmerkmale der Staatsorganisation in rechtlicher und entwicklungsgeschichtlicher Sicht ("Characteristics of State Organization from a Juristic and Developmental-Historical Viewpoint"), in 1964 he was awarded the title of professor, a title of academic distinction in Germany, and taught at the University of Munich until 1966.
Simplified: He wrote Die Wesensmerkmale der Staatsorganisation in rechtlicher und entwicklungsgeschichtlicher Sicht ("Characteristics of State Organization from a Juristic and Developmental-Historical Viewpoint"), and was given the title of professor in 1964.