Originals are open to archival visit etc, cf. www.uniklinik-duesseldorf.de/vester
Via Zenodo, a growing number of questionnaires with enclosures and index cards will be published open access on the internet, catalogued by means of Kalliope, the central portal for personal archives in german-language countries, cf. (with index):
https://kalliope-verbund.info/findingaid?fa.id=DE-611-BF-70963
[repository: https://kalliope-verbund.info/DE-611-BF-70963]