Columbia subject headings:
Koeppen, Wolfgang, 1906-1996--Correspondence.
Unseld, Siegfried--Correspondence.
Harvard subject headings:
Authors and publishers--Germany.
Authors, German--20th century--Correspondence
Koeppen, Wolfgang, 1906-1996--Correspondence.
Publishers and publishing--Germany--Correspondence
Unseld, Siegfried--Correspondence.
Princeton subject headings:
Koeppen, Wolfgang, 1906-1996--Correspondence.
Personal correspondence.
Unseld, Siegfried--Correspondence.