Columbia subject headings:
Bombers.
Great Britain. Royal Air Force. Bomber Command--History.
World War, 1939-1945--Aerial operations, British.
Harvard subject headings:
Bombers.
Great Britain. Royal Air Force. Bomber Command--History.
World War, 1939-1945--Aerial operations, British.
Princeton subject headings:
Bombers--History.
Great Britain. Royal Air Force. Bomber Command--History.
World War, 1939-1945--Aerial operations, British.