Columbia subject headings:
Cologne (Germany)--History, Military.
Cologne (Germany)--Politics and government.
Cologne (Germany)--Social conditions.
Harvard subject headings:
Cologne (Germany)--History, Military.
Cologne (Germany)--Politics and government.
Cologne (Germany)--Social conditions.
Princeton subject headings:
Cologne (Germany)--History, Military.
Cologne (Germany)--Politics and government.
Cologne (Germany)--Social conditions.