Veenendaal, A.J. β€œIn Memoriam Dr. H.A. Enno Van Gelder 1889-1973”. BMGN - Low Countries Historical Review 88, no. 3 (January 1, 1973): 470–471. Accessed November 21, 2024. https://bmgn-lchr.nl/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-107753.