E.J. Harenberg, Oorkondenboek van Gelre en Zutphen tot 1326. BMGN - Low Countries Historical Review, [S. l.], v. 100, n. 2, p. 269–272, 1985. DOI: 10.18352/bmgn-lchr.2591. Disponível em: https://ojstest.minions.amsterdam/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102814.. Acesso em: 26 nov. 2024.