Columbia subject headings:
Poland--History--Occupation, 1939-1945--Sources.
Poland--Politics and government--1918-1945--Sources.
Polska Partia Socjalistyczna--History--Sources.
Socialism--Poland--History--20th century--Sources.
Socialist parties--Poland--History--20th century--Sources.
Socialists--Poland--Correspondence.
World War, 1939-1945--Underground movements--Poland--Sources.
Harvard subject headings:
Princeton subject headings:
Poland--History--Occupation, 1939-1945--Sources.
Polska Partia Socjalistyczna--History--Sources.
Socialism--Poland--History--20th century--Sources.
Socialists--Poland--Correspondence.
World War, 1939-1945--Underground movements--Poland--Sources.