“T.J. Hoekstra, Liber Castellorum. 40 Variaties Op Het Thema Kasteel”. BMGN - Low Countries Historical Review 102, no. 4 (January 1, 1987): 633–634. Accessed June 30, 2024. https://ojstest.minions.amsterdam/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-103211.