Columbia subject headings:
Grassland ecology--Great Plains.
Great Plains--Antiquities.
Indians of North America--Great Plains--Antiquities.
Paleoecology--Great Plains.
Harvard subject headings:
Grassland ecology--Great Plains.
Great Plains--Antiquities.
Indians of North America--Great Plains--Antiquities.
Paleoecology--Great Plains.
Princeton subject headings:
Grassland ecology--Great Plains.
Great Plains--Antiquities.
Indians of North America--Great Plains--Antiquities.
Paleoecology--Great Plains.