Columbia subject headings:
Labor unions--Brazil--History--Sources.
Socialism--Brazil--History--Sources.
Working class--Brazil--History--Sources.
Harvard subject headings:
Labor unions--Brazil--History--Sources.
Socialism--Brazil--History--Sources.
Socialism--Brazil--Sources.
Working class--Brazil--History--Sources.
Princeton subject headings:
Labor unions--Brazil--History--Sources.
Socialism--Brazil--History--Sources.
Working class--Brazil--History--Sources.