Columbia subject headings:
Poland--History--German occupation, 1914-1918.
Polish question.
Soviet Union--History--Revolution, 1917-1921.
World War, 1914-1918--Diplomatic history.
Harvard subject headings:
Poland--History--German occupation, 1914-1918
Polish question.
Soviet Union--History--Revolution, 1917-1921.
World War, 1914-1918--Diplomatic history
Princeton subject headings:
Poland--History--German occupation, 1914-1918.
Polish question.
Soviet Union--History--Revolution, 1917-1921.
World War, 1914-1918--Diplomatic history.