Columbia subject headings:
Harvard subject headings:
London (England)--History--Bombardment, 1940-1941.
World War, 1939-1945--Aerial operations, German.
World War, 1939-1945--Campaigns--England--London.
Princeton subject headings:
Harbors--England--London--History.
London (England)--History--Bombardment, 1940-1945.
World War, 1939-1945--Riverine operations--England--London.