Columbia subject headings:
Harvard subject headings:
World War, 1914-1918--Austria
World War, 1914-1918--Causes
World War, 1914-1918--Germany.
World War, 1914-1918--United States
Princeton subject headings:
World War, 1914-1918--Austria.
World War, 1914-1918--Causes.
World War, 1914-1918--Germany.
World War, 1914-1918--United States.