Columbia subject headings:
Cities and towns--Europe, Eastern--Congresses.
Cities and towns--Europe, Southern--Congresses.
Harbors--Europe, Eastern--Congresses.
Harbors--Europe, Southern--Congresses.
Harvard subject headings:
Cities and towns--Europe, Eastern--History.
Europe, Eastern--Commerce--History.
Europe, Eastern--History.
Harbors--Europe, Eastern--History.
Princeton subject headings: