Bornebroek, Arno. “Herman Langeveld, De Man Die in De Put Sprong. Willem Schermerhorn 1894-1977”. TSEG - The Low Countries Journal of Social and Economic History 11, no. 3 (September 15, 2014): 215–217. Accessed April 26, 2024. https://tseg.nl/article/view/7435.