Columbia subject headings:
Harvard subject headings:
Europe--Commerce--History--Congresses.
Europe--History, Naval--Congresses.
Navigation--Europe--History--Congresses.
Shipping--Europe--History--Congresses.
Princeton subject headings:
Europe--Commerce--History--Congresses.
Europe--History, Naval--Congresses.
Navigation--Europe--History--Congresses.
Shipping--Europe--History--Congresses.