Columbia subject headings:
Petroleum industry and trade--Brazil.
Petróleo Brasileiro, S.A.
Harvard subject headings:
Government monopolies--Brazil.
Petroleum industry and trade--Brazil
Petroleum industry and trade--Government ownership--Brazil.
Petróleo Brasileiro, S.A.
Princeton subject headings:
Government monopolies--Brazil.
Petroleum industry and trade--Government ownership--Brazil.
Petróleo Brasileiro, S.A.