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