The permanent collection of Georg Stahl's works can be viewed at the Ståhl Collection in Norrköping, Sweden. This collection spans from the late 1950s to the present day and complements the Norrköping Art Museum.
You can find more details in this article from Christie's: The Ståhl Collection in Norrköping.
Here are some images from the collection:
For more information and to get a closer look at the works, you may want to visit their official website or plan a visit to Norrköping.