Columbia subject headings:
Harvard subject headings:
Arras, Battle of, Arras, France, 1917.
Saint-Mihiel, Battle of, Saint-Mihiel, France, 1918.
World War, 1914-1918--Aerial operations, American
World War, 1914-1918--Aerial operations, British
World War, 1914-1918--Aerial operations, French
World War, 1914-1918--Aerial operations, German
Princeton subject headings:
Arras, Battle of, Arras, France, 1917.
Saint-Mihiel, Battle of, Saint-Mihiel, France, 1918.
World War, 1914-1918--Aerial operations, American.
World War, 1914-1918--Aerial operations, British.
World War, 1914-1918--Aerial operations, French.
World War, 1914-1918--Aerial operations, German.