VELS HEIJN, A. A. E. In memoriam Willy Halsema-Kubes. The Rijksmuseum Bulletin, [S. l.], v. 40, n. 2, p. 135–137, 1992. DOI: 10.52476/trb.20562. Disponível em: https://testplatform.openjournals.nl/the-rijksmuseum-bulletin/article/view/20562. Acesso em: 11 apr. 2026.