Columbia subject headings:
Borderlands--European Union countries.
Borderlands--Germany--History--20th century.
Borderlands--Poland--History--20th century.
European Union countries--Foreign relations.
Harvard subject headings:
Borderlands--European Union countries.
Borderlands--Germany--History--20th century.
Borderlands--Poland--History--20th century.
European Union countries--Foreign relations.
Princeton subject headings:
Borderlands--European Union countries.
Borderlands--Germany--History--20th century.
Borderlands--Poland--History--20th century.
European Union countries--Foreign relations.