Columbia subject headings:
Bloco Operário e Camponês do Brasil--History.
Communism--Brazil--History--20th century.
Harvard subject headings:
Bloco Operário e Camponês do Brasil--History.
Communism--Brazil--History--20th century
Princeton subject headings:
Bloco Operário e Camponês do Brasil--History.
Communism--Brazil--History--20th century.