Columbia subject headings:
Harvard subject headings:
Education--Germany--History
Havenstein, Martin, 1871-1945--Correspondence.
Schumann, Otto, 1888-1950--Correspondence.
Teachers--Germany--Correspondence.
Princeton subject headings:
Havenstein, Martin, 1871-1945--Correspondence.
High school teachers--Germany--Correspondence.
National socialism and education.
Schumann, Otto, 1888-1950--Correspondence.