Columbia subject headings:
Harvard subject headings:
Energy industries--Canada--Yearbooks.
Gas industry--Canada--Yearbooks.
Natural gas--Canada--Periodicals.
Petroleum industry and trade--Canada--Periodicals.
Petroleum industry and trade--Canada--Yearbooks.
Power resources--Canada--Periodicals.
Princeton subject headings:
Energy industries--Canada--Periodicals.
Gas industry--Canada--Periodicals.
Natural gas--Canada--Periodicals.
Petroleum industry and trade--Canada--Periodicals.
Power resources--Canada--Periodicals.