T. J. A. Reijers. (1973). Stratigraphy, sedimentology and palaeogeography of Eifelian, Givetian and Frasnian strata between the river Porma and the Embalse de la Luna, Cantabrian Mountains, Spain. Netherlands Journal of Geosciences, 115-124. Retrieved from https://njgjournal.nl/index.php/njg/article/view/14497