British regional geology: South Wales,
J. Pringle b. 1877. (John), T. Neville George 1904- (Thomas Neville),; Geological Survey of Great Britain; Museum of Practical Geology (Great Britain)
London, H.M. Stationery Off. 1948
Disponible en IGC - Instituto de Geociências (554.2 P957b 2.ed. )(Obténgalo)