Columbia subject headings:
Harvard subject headings:
European Union countries--Economic conditions
European Union countries--Politics and government
European Union countries--Social conditions.
Science--European Union countries--History.
Technology--European Union countries--History.
Princeton subject headings:
European Union countries--Economic conditions.
European Union countries--Politics and government.
European Union countries--Social conditions.
Science--European Union countries--History.
Technology--European Union countries--History.