LEHMANN, H. Die Erdölvorräte Nordwest-Deutschlands. ERDKUNDE, [S. l.], v. 2, n. 2, p. 331–333, 1948. DOI: 10.3112/erdkunde.1948.02.12. Disponível em: https://journals-test.ulb.uni-bonn.de/index.php/erdkunde/article/view/899. Acesso em: 8 oct. 2024.