Columbia subject headings:
Harvard subject headings:
Industrial location--Germany--North Rhine-Westphalia.
Investments, American--Germany--North Rhine-Westphalia.
North Rhine-Westphalia (Germany)--Investments.
Princeton subject headings:
Industrial location--Germany--North Rhine-Westphalia.
Investments, American--Germany--North Rhine-Westphalia.
North Rhine-Westphalia (Germany)--Investments.