KÜPPER, M. Der Gesamtkatalog der Düsseldorfer Kulturinstitute (GDK). AKMB-news: Informationen zu Kunst, Museum und Bibliothek, [S. l.], v. 2, n. 2, p. 20–23, 2009. DOI: 10.11588/akmb.1996.2.315. Disponível em: https://journals.ub.uni-heidelberg.de/index.php/akmb-news/article/view/315. Acesso em: 7 mai. 2024.