Columbia subject headings:
Contraband of war.
Neutrality.
World War, 1914-1918--Blockades.
World War, 1914-1918--Economic aspects--United States.
Harvard subject headings:
Contraband of war.
Neutrality.
World War, 1914-1918--Blockades
World War, 1914-1918--Economic aspects--United States
Princeton subject headings: