Columbia subject headings:
Harvard subject headings:
European Union--Germany.
European federation.
Oppenheim, Friedrich Carl von, 1900-1978.
Princeton subject headings:
Europa-Union Deutschland--Sources.
Europe--Politics and government--20th century.
European Union--Germany.
European Union--History.
European federation--History--Sources.
European federation--History.
Germany--Politics and government--1945-1990.
Oppenheim, Friedrich Carl von, 1900-1978.