KNOTTER, Ad. Ten geleide. Studies over de sociaaleconomische geschiedenis van Limburg, [S. l.], v. 52, p. 3–6, 2007. DOI: 10.58484/ssegl.v52i12478. Disponível em: https://testplatform.openjournals.nl/SSEGL/article/view/12478. Acesso em: 11 apr. 2026.