Columbia subject headings:
Authors, German--20th century--Correspondence.
Böll, Heinrich, 1917-1985--Correspondence.
Harvard subject headings:
Authors, German--20th century--Correspondence
Böll, Heinrich, 1917-1985--Correspondence.
Princeton subject headings:
Authors, German--20th century--Correspondence.
Böll, Heinrich, 1917-1985--Correspondence.