“J.S. Calff, Van Pionier Tot Mammoet. Het Amsterdamse Montessori Lyceum, 1930-1980”. BMGN - Low Countries Historical Review 98, no. 2 (January 1, 1983): 258–260. Accessed July 2, 2024. https://ojstest.minions.amsterdam/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-102605.