Columbia subject headings:
Germany. Heer--History--World War, 1939-1945.
World War, 1939-1945--Campaigns--Eastern Front.
World War, 1939-1945--Germany.
Harvard subject headings:
Princeton subject headings:
Poland--History--Occupation, 1939-1945.
World War, 1939-1945--Campaigns--Germany.
World War, 1939-1945--Campaigns--Poland.