Helmig, H. M. (1965). The geology of the Valderrueda, Tejerina, Ocejo and Sabero Coal Basins: Cantabrian mountains, Spain. Thesis Univ. Leiden.
Chicago Style (17th ed.) CitationHelmig, H. M. The Geology of the Valderrueda, Tejerina, Ocejo and Sabero Coal Basins: Cantabrian Mountains, Spain. Leiden: Thesis Univ. Leiden, 1965.
MLA (9th ed.) CitationHelmig, H. M. The Geology of the Valderrueda, Tejerina, Ocejo and Sabero Coal Basins: Cantabrian Mountains, Spain. Thesis Univ. Leiden, 1965.
Warning: These citations may not always be 100% accurate.