Columbia subject headings:
Bus lines--Government ownership--Mexico--Mexico City--Cost effectiveness.
Local transit--Mexico--Mexico City.
Transportation and state--Mexico--Mexico City.
Transportation--Mexico--Mexico City.
Harvard subject headings:
Bus lines--Government ownership--Mexico--Mexico City--Cost effectiveness.
Local transit--Mexico--Mexico City.
Transportation and state--Mexico--Distrito Federal.
Transportation and state--Mexico--Mexico City.
Transportation--Mexico--Mexico City.
Princeton subject headings:
Bus lines--Government ownership--Mexico--Mexico City--Cost effectiveness.
Local transit--Mexico--Mexico City.
Transportation and state--Mexico--Distrito Federal.
Transportation and state--Mexico--Mexico City.
Transportation--Mexico--Mexico City.