E.J. Harenberg, Oorkondenboek van Gelre en Zutphen tot 1326, IV. BMGN - Low Countries Historical Review, [S. l.], v. 110, n. 1, p. 91–92, 1995. DOI: 10.18352/bmgn-lchr.3956. Disponível em: https://ojstest.minions.amsterdam/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-104550.. Acesso em: 30 jun. 2024.