H.J.L. Vonhoff, Liberalen onder één dak. VVD: 50 jaar liberale vereniging. BMGN - Low Countries Historical Review, [S. l.], v. 114, n. 4, p. 644–646, 1999. DOI: 10.18352/bmgn-lchr.5136. Disponível em: https://ojstest.minions.amsterdam/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-105884.. Acesso em: 22 dec. 2024.