J.J. Kelder, De Schalkhaarders. Nederlandse politiemannen naar nationaal-socialistische snit. BMGN - Low Countries Historical Review, [S. l.], v. 108, n. 1, p. 114–116, 1993. DOI: 10.18352/bmgn-lchr.3642. Disponível em: https://ojstest.minions.amsterdam/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-104175.. Acesso em: 16 sep. 2024.