From the German Wikipedia page [1]

The City Archives Unna], Germany manages the archival material from the administration and sources of contemporary history. Among other things, it has a library with more than 1500 volumes on the history of Unna and the Hellweg region [2] in Germany. As a city archivist, Willy Timm established the archive. The archive is currently managed by Thomas Wardenga.

The website is [3]