Columbia subject headings:
Harbors--Italy--Tuscany--History.
Harbors--Spain--Catalonia--History.
Mediterranean Region--Commerce--History.
Harvard subject headings:
Harbors--Italy--Tuscany--History.
Harbors--Spain--Catalonia--History.
Mediterranean Region--Commerce--History.
Princeton subject headings:
Harbors--Italy--Tuscany--History.
Harbors--Spain--Catalonia--History.
Mediterranean Region--Commerce--History.