Columbia subject headings:
Petroleum industry and trade--Canada--Congresses.
Petroleum industry and trade--Persian Gulf Region--Congresses.
Harvard subject headings:
Petroleum industry and trade--Canada--Congresses.
Petroleum industry and trade--Persian Gulf Region--Congresses.
Princeton subject headings:
Petroleum industry and trade--Canada--Congresses.
Petroleum industry and trade--Persian Gulf Region--Congresses.