Columbia subject headings:
Harvard subject headings:
Competition--European Union countries--Congresses.
Competition--Germany--Congresses.
Energy industries--European Union countries--Congresses.
Energy industries--Germany--Congresses.
Princeton subject headings:
Competition--European Union countries--Congresses.
Competition--Germany--Congresses.
Energy industries--European Union countries--Congresses.
Energy industries--Germany--Congresses.