Fortuin, AR. 1984. Late Ordovician glaciomarine deposits (Orea Shale) in the Sierra de Albarracin, Spain. Palaeogeography, Palaeoclimatology, Palaeoecology 48,24-261.
Gutierrez-Marco, J.C. & Storch, P. 1998. Graptolite biostratigraphy of the Lower Silurian (Llandovery) shelf deposits of the Western Iberian Cordillera, Spain. Geological Magazine 135, 71-92.
Gutierrez-Marco, J.C., Robardet, M., Rabano, I., Sarmiento, G.N., San José Lancha, M.A, Herranz Araujo, P. & Pieren Pidal, AP. 2002. Ordovician. In: Gibbons, W. & Moreno, M. T. (eds). The Geology of Spain. The Geological Society, London, 31-50.