BOSMANS, J.L.J. M. Eekman, H. Pieterson, Linkssocialisme tussen de wereldoorlogen. Twee studies. BMGN - Low Countries Historical Review, [S. l.], v. 104, n. 3, p. 478–479, 1989. DOI: 10.18352/bmgn-lchr.3158. Disponível em: https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-103553.. Acesso em: 7 oct. 2024.