Columbia subject headings:
Europe--History--1918-1945.
Polish people--Europe--History--20th century.
World War, 1939-1945--Poland.
World War, 1939-1945--Underground movements--Europe.
Harvard subject headings:
Europe--History--1918-1945.
Polish people--Europe--History--20th century.
World War, 1939-1945--Poland.
World War, 1939-1945--Underground movements--Europe.
Princeton subject headings:
Polish people--Europe.