1. Barker R. (1990) Entity Relationship Modelling (Addison-Wesley Publishing Company, Workingham).
2. Bickermore D. P. Kelk B. (1972) Proceedings of Twenty-Fourth International Geological Congress Production of a multi-coloured geological map by automated means, 16, pp 121–127.
3. Boulter C. A. (1989) Four Dimensional Analysis of Geological Maps (Wiley, Chichester).
4. Brandon A. Sumbler M. G. Ivimey-Cook H. C. (1990) Proceedings of the Yorkshire Geological Society A revised lithostratigraphy for the Lower and Middle Lias (Lower Jurassic) east of Nottingham, 48, pp 121–141.
5. Loudon T. V. Clifton A. W. Giles J. R. A. Holmes K. A. Laxton J. L. Mennim K. C. (1991) Applied Geological Mapping in the Wrexham Area—Computing Techniques, British Geological Survey Technical Report, WO/91/1.