LEUPEN, P. Nogmaals Beek en de stamvader van de Bosoniden. BMGN - Low Countries Historical Review, [S. l.], v. 93, n. 3, p. 446–449, 1978. DOI: 10.18352/bmgn-lchr.2049. Disponível em: https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102220. Acesso em: 19 jan. 2022.