Columbia subject headings:
Harvard subject headings:
Europe--History--20th century.
Germany--History--20th century.
World War, 1914-1918
World War, 1914-1918--Europe.
World War, 1914-1918--Germany.
Princeton subject headings:
Europe--Civilization--20th century.
Europe--History--1918-1945.
Germany--Civilization--20th century.
Germany--History--1918-1933.
World War, 1914-1918.