Columbia subject headings:
Harvard subject headings:
Imperialism--History--20th century
Poland--History--20th century--Sources.
Poland--History--German occupation, 1914-1918
Poland--History--Occupation, 1939-1945
World War, 1914-1918--Poland
World War, 1939-1945--Poland.
Princeton subject headings:
Imperialism--History--20th century.
Poland--History--20th century--Sources.
Poland--History--German occupation, 1914-1918.
Poland--History--Occupation, 1939-1945.
World War, 1914-1918--Poland.
World War, 1939-1945--Poland.