Columbia subject headings:
Duisburg (Germany)--Court and courtiers.
Duisburg (Germany)--History--Pictorial works.
Duisburg (Germany)--History.
Palaces--Germany--Duisburg--History.
Harvard subject headings:
Duisburg (Germany)--Court and courtiers.
Duisburg (Germany)--History--Pictorial works.
Duisburg (Germany)--History.
Palaces--Germany--Duisburg--History.
Princeton subject headings:
Duisburg (Germany)--Court and courtiers.
Duisburg (Germany)--History--Pictorial works.
Duisburg (Germany)--History.
Palaces--Germany--Duisburg--History.