Heering, A. “J. Frieswijk, Ferdinand Domela Nieuwenhuis. De Apostel Van De Friese Arbeiders”. BMGN - Low Countries Historical Review 105, no. 3 (January 1, 1990): 466–467. Accessed May 6, 2024. https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-103736.