Columbia subject headings:
World War, 1914-1918--Bibliography.
World War, 1914-1918--Causes--Bibliography.
Harvard subject headings:
World War, 1914-1918--Bibliography
World War, 1914-1918--Causes--Bibliography.
Princeton subject headings:
World War, 1914-1918--Bibliography.
World War, 1914-1918--Causes--Bibliography.