Boogman, J.C. “Federalism. History and Current Significance of a Form of Government. Introduction”. BMGN - Low Countries Historical Review 94, no. 3 (January 1, 1979): 373–376. Accessed March 29, 2024. https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102289.