The tenth-century Holy-Cross chapel (Heilig-Kruiskapel) in Utrecht and its relation to Willibrord. Bulletin KNOB, [S. l.], v. 107, n. 3, p. 81–89, 2008. DOI: 10.7480/knob.107.2008.3.173. Disponível em: https://bulletin.knob.nl/index.php/knob/article/view/Broer81. Acesso em: 20 apr. 2026.