KRUL, W. P. van Hees, G. Puchinger, Briefwisseling Gerretson-Van Eyck. BMGN - Low Countries Historical Review, [S. l.], v. 100, n. 3, p. 497–499, 1985. DOI: 10.18352/bmgn-lchr.2647. Disponível em: https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102872. Acesso em: 19 apr. 2024.