	Authors	Year	Title
	Kullmann, Wagner & Winkler_Prins	2007	Significance for international correlation of the Perapertú Formation in Northern Palencia, Cantabrian Mountains. Tectonic/stratigraphic context and description of Mississippian and Upper Bashkirian Goniatites. Revista Española de Paleontología, 22 (2), 127-145, 8 fig., Madrid.
	Wagner, Winkler_Prins & Riding	1971	Lithostratigraphic units of the lower part of the Carboniferous in Northern León, Spain [with a Note on some Goniatite Faunas by C.H.T. Wagner-Gentis]. Trabajos de Geología, 4: 603-663, fig.1-10, pl.1-3; Oviedo.
	Wagner & Winkler_Prins	2000	Carboniferous stratigraphy of the Sierra del Brezo in northern Palencia: evidence of major uplifts. Trabajos de Geología, 21: 385-403, 6 fig., Ovedo.