Columbia subject headings:
Harvard subject headings:
Geology--England--Congresses.
Geology--North Sea--Congresses.
Morphotectonics--North Sea--Congresses.
Natural gas in submerged lands--North Sea.
Petroleum in submerged lands--North Sea.
Petroleum--Geology--England--Congresses.
Petroleum--Geology--North Sea--Congresses.
Princeton subject headings:
Geology--North Sea Region.
Natural gas--Geology--North Sea Region.
Petroleum--Geology--North Sea Region.