Columbia subject headings:
World War, 1914-1918--Blockades.
World War, 1914-1918--Naval operations, British.
Harvard subject headings:
World War, 1914-1918--Blockades
World War, 1914-1918--Naval operations, British
Princeton subject headings:
Germany--Foreign economic relations--Great Britain--History--20th century.
Great Britain--Foreign economic relations--Germany--History--20th century.
World War, 1914-1918--Blockades--Germany.
World War, 1914-1918--Naval operations, British.