Bouguer gravity anomaly map, 1:1,000,000 series: northern North Sea sheet / 
Tully, M. C.
[London] :  Institute Geological Sciences, 
1983.
With: 1:1000000 northern North Sea Bouguer anomaly gravity map. [By] D.C. Tully and J.A. Donato. (BGS report; vol. 16, no. 6).