Deeken, H. W. (1968). Investigation of the National Potential for the Advancement of the Teaching of German in the United States. Philadelphia: National Carl Schurz Association, Inc., American Association of Teachers of German, Inc..

Deeken, Hans W. Investigation of the National Potential for the Advancement of the Teaching of German in the United States. Philadelphia: National Carl Schurz Association, Inc., American Association of Teachers of German, Inc., 1968.

Deeken, Hans W. Investigation of the National Potential for the Advancement of the Teaching of German in the United States. Philadelphia: National Carl Schurz Association, Inc., American Association of Teachers of German, Inc., 1968.