Columbia subject headings:
Harvard subject headings:
European Union
Germany--Boundaries--Poland.
Germany--Relations--Poland.
Poland--Boundaries--Germany
Poland--Relations--Germany
Social integration--Germany.
Social integration--Poland.
Princeton subject headings:
European Union.
Germany--Boundaries--Poland.
Germany--Relations--Poland.
Poland--Boundaries--Germany.
Poland--Relations--Germany.
Social integration--Germany.
Social integration--Poland.