J.E. Burger, Linkse frontvorming. Samenwerking van revolutionaire socialisten 1914-1918. BMGN - Low Countries Historical Review, [S. l.], v. 100, n. 3, p. 491–492, 1985. DOI: 10.18352/bmgn-lchr.2643. Disponível em: https://ojstest.minions.amsterdam/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102868.. Acesso em: 22 dec. 2024.