Columbia subject headings:
Danube River Valley--Commerce--History.
Danube River--Commerce--History.
Inland water transportation--Danube River Valley--History.
Shipping--Danube River Valley--History.
Turkey--History--Ottoman Empire, 1288-1918.
Harvard subject headings:
Danube River Valley--Commerce--History.
Danube River--Commerce--History.
Inland water transportation--Danube River Valley--History.
Shipping--Danube River Valley--History.
Turkey--History--Ottoman Empire, 1288-1918.
Princeton subject headings:
Danube River Valley--Commerce--History.
Danube River--Commerce--History.
Inland water transportation--Danube River Valley--History.
Shipping--Danube River Valley--History.
Turkey--History--Ottoman Empire, 1288-1918.