Columbia subject headings:
Harvard subject headings:
Labor unions--Colombia--Bogotá--History.
Labor unions--Colombia--Medellín--History.
Working class--Colombia--Bogotá--History.
Working class--Colombia--Medellín--History.
Princeton subject headings:
Labor unions--Colombia--Bogotá--History.
Labor unions--Colombia--Medellín--History.
Working class--Colombia--Bogotá--History.
Working class--Colombia--Medellín--History.