van Loevezijn, Gerard. “Frasnian (Upper Devonian) Lithostratigraphy of the Bernesga Valley (Cantabrian Mountains, NW Spain)”. Geologos 31, no. 2 (September 9, 2025): 99–117. Accessed December 7, 2025. https://pressto.amu.edu.pl/index.php/logos/article/view/49440.