KNOTTER, Ad. Ten geleide. Studies over de sociaaleconomische geschiedenis van Limburg, [S. l.], v. 50, p. 3–4, 2005. DOI: 10.58484/ssegl.v50i12512. Disponível em: https://testplatform.openjournals.nl/SSEGL/article/view/12512. Acesso em: 11 apr. 2026.