Columbia subject headings:
Harvard subject headings:
Gossweiler, Kurt--Correspondence.
Hacks, Peter, 1928-2003--Correspondence.
Hacks, Peter, 1928-2003--Political and social views.
Princeton subject headings:
Gossweiler, Kurt--Correspondence.
Hacks, Peter, 1928-2003--Correspondence.
Hacks, Peter, 1928-2003--Views on politics.
Socialists--Germany--Correspondence.