HOFFMANN, Karl Walter. Planning and Evaluating Geography Lessons with the National Standards for Education. Journal of Geography Education, [S. l.], v. 37, n. 3, p. 105–119, 2009. DOI: 10.60511/zgd.v37i3.202. Disponível em: https://zgd-journal.de/index.php/zgd/article/view/202. Acesso em: 2 apr. 2026.