Columbia subject headings:
Authors, German--20th century--Correspondence.
Hacks, Peter, 1928-2003--Correspondence.
Harvard subject headings:
Hacks, Peter, 1928---Correspondence.
Hacks, Peter, 1928-2003--Correspondence.
Princeton subject headings:
Authors, German--20th century--Correspondence.
Hacks, Peter, 1928-2003--Correspondence.