Columbia subject headings:
Harvard subject headings:
World War, 1914-1918--Aerial operations, American
World War, 1914-1918--Aerial operations, British
World War, 1914-1918--Casualties--Statistics
Princeton subject headings:
Statistics.
World War, 1914-1918--Aerial operations, American.
World War, 1914-1918--Aerial operations, British.
World War, 1914-1918--Casualties--Statistics.