Columbia subject headings:
Etla Valley (Mexico)--History.
Water use--Law and legislation--Mexico--Etla Valley--History.
Water use--Mexico--Etla Valley--History.
Water-supply--Mexico--Etla Valley--History.
Harvard subject headings:
Princeton subject headings:
Etla Valley (Mexico)--Economic conditions.
Water-supply--Law and legislation--Mexico--Etla Valley--History.
Water-supply--Mexico--Etla Valley--History.