Columbia subject headings:
Communism--Portugal--History--20th century.
Partido Comunista Português--History.
Portugal--Politics and government--1910-1974.
Harvard subject headings:
Communism--Portugal--History--20th century.
Partido Comunista Português--History.
Portugal--Politics and government--1910-1974.
Princeton subject headings:
Communism--Portugal--History--20th century.
Partido Comunista Português--History.
Portugal--Politics and government--1910-1974.