Columbia subject headings:
Energy conservation--Denmark--Periodicals.
Energy policy--Denmark--Periodicals.
Power resources--Denmark--Periodicals.
Harvard subject headings:
Energy conservation--Denmark--Periodicals.
Energy consumption--Denmark--Periodicals.
Energy policy--Denmark--Periodicals.
Power resources--Denmark--Periodicals.
Princeton subject headings:
Energy conservation--Denmark--Periodicals.
Energy policy--Denmark--Periodicals.
Periodicals.
Power resources--Denmark--Periodicals.