BIRKENHAUER, Josef. Geographieunterricht und Allgemeinbildung. Journal of Geography Education, [S. l.], v. 16, n. 4, p. 173–182, 1988. DOI: 10.60511/zgd.v16i4.402. Disponível em: https://zgd-journal.de/index.php/zgd/article/view/402. Acesso em: 2 apr. 2026.