J. Frieswijk, Socialisme in Friesland 1880-1900. BMGN - Low Countries Historical Review, [S. l.], v. 94, n. 2, p. 316–317, 1979. DOI: 10.18352/bmgn-lchr.2108. Disponível em: https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102284.. Acesso em: 18 jul. 2024.