Columbia subject headings:
Harvard subject headings:
Balkan Peninsula--Commerce--History.
Balkan Peninsula--History, Naval.
Europe, Eastern--Commerce--History.
Europe, Eastern--History, Naval.
Europe, Southern--Commerce--History.
Europe, Southern--History, Naval.
Merchant marine--Balkan Peninsula--History.
Merchant marine--Europe, Eastern--History.
Merchant marine--Europe, Southern--History.
Princeton subject headings:
Balkan Peninsula--Commerce--History.
Balkan Peninsula--History, Naval.
Merchant marine--Balkan Peninsula--History.
Merchant marine--Southeastern Europe--History.