Columbia subject headings:
Harvard subject headings:
Labor unions--Mexico--History.
Working class--Mexico--History
Princeton subject headings:
Cárdenas, Lázaro, 1895-1970.
Labor unions--Mexico--Political activity--History--20th century.
Mexico--Politics and government--1910-1946.
Political parties--Mexico--History--20th century.
Working class--Mexico--Political activity--History--20th century.