Columbia subject headings:
Harvard subject headings:
Economics, Prehistoric--North America.
Indians of North America--Agriculture.
Indians of North America--Economic conditions.
Indians of South America--Agriculture
Indians of South America--Economic conditions.
Irrigation--America.
Irrigation--North America.
Paleo-Indians--Water-supply.
Water--Management.
Princeton subject headings:
Economics, Prehistoric--North America.
Indians of North America--Agriculture.
Indians of North America--Economic conditions.
Irrigation--North America.
Paleo-Indians--Water-supply.
Water--Management.