Columbia subject headings:
Communism--Mexico--History--20th century.
Labor movement--Mexico--History--20th century.
Harvard subject headings:
Communism--Mexico--History--20th century.
Labor movement--Mexico--History--20th century
Princeton subject headings:
Communism--Mexico--History--20th century.
Confederación de Trabajadores de México.
Labor movement--Mexico--History--20th century.
Labor unions--Mexico--History--20th century.