BOSMANS, J. J.W.M. Engels, De Minister zonder Portefeuille. BMGN - Low Countries Historical Review, [S. l.], v. 104, n. 3, p. 480–482, 1989. DOI: 10.18352/bmgn-lchr.3160. Disponível em: https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-103555. Acesso em: 28 mar. 2024.