Columbia subject headings:
Authors, German--20th century--Correspondence.
Schulz, Helmut Hermann--Correspondence.
Harvard subject headings:
Authors, German--20th century--Correspondence
Germany--History--Unification, 1990.
Schulz, Helmut Hermann--Correspondence.
Princeton subject headings:
Authors, German--20th century--Correspondence.
Schulz, Helmut Hermann--Correspondence.