Columbia subject headings:
Community organization--Germany--North Rhine-Westphalia.
Housing, Cooperative--Germany--North Rhine-Westphalia.
Harvard subject headings:
Community organization--Germany--North Rhine-Westphalia.
Housing, Cooperative--Germany--North Rhine-Westphalia.
Princeton subject headings:
Cooperative societies--Germany (West)--North Rhine-Westphalia--History.
Housing, Cooperative--Germany (West)--North Rhine-Westphalia--History.