Robins, Nicholas; MacDonald, Alan; Allen, David. 2007 The vulnerability paradox for hard fractured lower palaeozoic and precambrian rocks. In: Witkowski, A.J.; Kowalczyk, A.; Vrba, J., (ed.) Selected papers from the Groundwater Vulnerability Assessment and Mapping International Conference, Ustron, Poland, 2004. Taylor & Francis, 13-19.