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