Half the Girardengos sold in Southern Germany were made by RIH Vienna iirc..

I didn't get a copy of the Mechanikerräder book, which I deeply regret.

If you're in love with those Viennese bikes, and are planning a trip to Europe, you may consider planning your trip around the "In Velo Veritas" event. It is a charming l'Eroica alternative in the vicinity of Vienna and you are very likely to bump into one or two of the authors of said book.
If you plan early, you may find someone local willing to lend you a bike even. They are nice people.