Columbia subject headings:
Hydraulic engineering--Mexico--Mexico, Valley of--History.
Indians of Mexico--Mexico--Mexico, Valley of--Antiquities.
Harvard subject headings:
Hydraulic engineering--Mexico--Mexico, Valley of--History.
Indians of Mexico--Mexico--Mexico, Valley of--Antiquities
Mexico--Antiquities.
Princeton subject headings:
Hydraulic engineering--Mexico--Mexico, Valley of--History.
Indians of Mexico--Mexico--Mexico, Valley of--Antiquities.