Columbia subject headings:
Black Sea Region--Antiquities.
Danube River Delta (Romania and Ukraine)--Antiquities.
Naval art and science--Danube River Delta (Romania and Ukraine)--History.
Romans--Romania.
Sea-power--Danube River Delta (Romania and Ukraine)--History.
Harvard subject headings:
Black Sea--History, Naval.
Danube River Valley--History, Naval.
Rome--History, Naval.
Rome--Navy
Sea-power--Black Sea.
Sea-power--Danube River Valley.
Princeton subject headings:
Black Sea Region--Antiquities.
Danube River Delta (Romania and Ukraine)--Antiquities.
Naval art and science--Danube River Delta (Romania and Ukraine)--History.
Sea-power--Danube River Delta (Romania and Ukraine)--History.