1. Sedimentology and stratigraphy of theTownsend Tuff Bed (Lower Old Red Sandstone) in South Wales and the Welsh Borders
2. Anderton, R. , Bridges, P.H., Leeder, M.R. & Sellwood, B.W. 1979. A Dynamic Stratigraphy of the British Isles. George Allen & Unwin, London.
3. Ballèvre, M. , Marchand, J., Godard, G., Goujou, J.-C. & Wyns, R. 1994. Eo-Hercynian events in the Armorican Massif. In: Keppie, J.D. (ed.) Pre-Mesozoic Geology in France and Adjacent Areas. Springer, Berlin, 183–194.