LILLJEQUIST, Robert. Jorden - en arret planet. Varv, [S. l.], v. 1993, n. 4, p. 121–128, 1993. DOI: 10.7146/varv.v1993i4.144438. Disponível em: https://tidsskrift.dk/varv/article/view/144438. Acesso em: 24 dec. 2025.