Columbia subject headings:
Harvard subject headings:
Germany--History--1789-1900.
Germany--Relations--Poland.
Poland--History--19th century
Poland--Relations--Germany
Princeton subject headings:
Germany--History--1789-1900.
Germany--History--1871-1918.
Germany--Relations--Poland.
Poland--History--19th century.
Poland--History--20th century.
Poland--Relations--Germany.