LEUPEN, P. De Karolingische villa Beek en de stamvader van de Bosoniden. BMGN - Low Countries Historical Review, [S. l.], v. 92, n. 3, p. 373–393, 1977. DOI: 10.18352/bmgn-lchr.2002. Disponível em: https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102166. Acesso em: 25 jan. 2022.