Columbia subject headings:
Mexico (City) Metropolitan Area--Transit systems.
Sistema de Transporte Colectivo--History.
Subways--Mexico--Mexico City Metropolitan Area--History.
Urban transportation--Mexico--Mexico City Metropolitan Area--History.
Harvard subject headings:
Mexico (City) Metropolitan Area--Transit systems.
Sistema de Transporte Colectivo--History.
Subways--Mexico--Mexico City Metropolitan Area--History.
Urban transportation--Mexico--Mexico City Metropolitan Area--History.
Princeton subject headings:
Mexico (City) Metropolitan Area--Transit systems.
Sistema de Transporte Colectivo--History.
Subways--Mexico--Mexico City Metropolitan Area--History.
Urban transportation--Mexico--Mexico City Metropolitan Area--History.