Columbia subject headings:
Portugal--History--1910-1974--Sources.
Portugal--Politics and government--1926-1933--Sources.
Underground literature--Portugal.
Harvard subject headings:
Government, Resistance to--Portugal--History--20th century--Sources.
Portugal--Politics and government--1926-1933--Sources.
Underground literature--Portugal--History--20th century.
Princeton subject headings:
Government, Resistance to--Portugal--History--20th century--Sources.
Portugal--Politics and government--1926-1933--Sources.
Underground literature--Portugal--History--20th century.