MELLINK, A. J. Engels, Zestig jaar socialistische beweging. BMGN - Low Countries Historical Review, [S. l.], v. 96, n. 1, p. 118–119, 1981. DOI: 10.18352/bmgn-lchr.2234. Disponível em: https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102413. Acesso em: 19 apr. 2024.