KNOTTER, Ad. Ten geleide. Studies over de sociaaleconomische geschiedenis van Limburg, [S. l.], v. 53, p. 3–5, 2008. DOI: 10.58484/ssegl.v53i12470. Disponível em: https://testplatform.openjournals.nl/SSEGL/article/view/12470. Acesso em: 11 apr. 2026.