Columbia subject headings:
Harvard subject headings:
Denmark--Kings and rulers--Congresses.
Europe, Northern--Kings and rulers--Congresses.
Princesses--Europe, Northern--History--Congresses.
Queens--Europe, Northern--Biography--Congresses.
Queens--Europe, Northern--History--Congresses.
Princeton subject headings:
Denmark--Kings and rulers--Congresses.
Europe, Northern--Kings and rulers--Congresses.
Princesses--Europe, Northern--History--Congresses.
Queens--Europe, Northern--Biography--Congresses.
Queens--Europe, Northern--History--Congresses.