Columbia subject headings:
Chaco War, 1932-1935--Causes.
Chaco War, 1932-1935--Economic aspects.
Petroleum industry and trade--Bolivia.
Petroleum industry and trade--Paraguay.
Harvard subject headings:
Chaco War, 1932-1935--Causes.
Chaco War, 1932-1935--Economic aspects.
Petroleum industry and trade--Bolivia
Petroleum industry and trade--Paraguay.
Princeton subject headings: