I.W. Lambrechtsen-van Essen, De stadspoorten van Leiden en stadsbouwmeester Willem van der Helm (c. 1628-1675). BMGN - Low Countries Historical Review, [S. l.], v. 111, n. 4, p. 548–549, 1996. DOI: 10.18352/bmgn-lchr.4363. Disponível em: https://ojstest.minions.amsterdam/article/view/URN%3ANBN%3ANL%3AUI%3A10-1-105037.. Acesso em: 16 nov. 2024.