Columbia subject headings:
Harvard subject headings:
Authors, German--20th century--Correspondence
Knobloch, Heinz, 1926-2003--Correspondence.
Pfeiffer, Rolf, 1932---Correspondence.
Princeton subject headings:
Knobloch, Heinz, 1926-2003--Correspondence.
Personal correspondence.
Pfeiffer, Rolf, 1932---Correspondence.