According to google translate, this is a revised version of a book that came out a few years ago. Available now.
A translated book description: "But the book is primarily about the individual secret production sites such as B. in St. Astier / France, Avia / Prague, Günzburg, Gablungen, Rüsselsheim, Kematen, Schwaz, Kahle, Landsberg, Eschenlohe, Kitzingen, Obertraubling, Gauting, Cham, Erging, Mühldorf ..... Forests were used , Mine tunnels, tunnels, super bunkers, parts of the wonder plane were built in many dozen provisional production facilities."
https://www.amazon.de/Messerschmitt-.../dp/3613042584
Usual disclaimer,
Ed