Blom, J.C.H. “P.F. Maas, Kabinetsformaties 1959-1973”. BMGN - Low Countries Historical Review 100, no. 2 (January 1, 1985): 330–333. Accessed November 21, 2024. https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102847.