SØRENSEN, Henning. Danmarks råstoffer skal nu kortlægges,. Varv, [S. l.], v. 1977, n. 2, p. 55–64, 1977. DOI: 10.7146/varv.v1977i2.149852. Disponível em: https://tidsskrift.dk/varv/article/view/149852. Acesso em: 7 dec. 2025.