OBEN: Photo Timo Bechtoldt, D. GRUEN & SONS Glashütte i. Sa. GmbH: SAECHSISCHESCHWEIZ - OSTERZGEBIRGE, Basteibrücke

LINKS:

http://vintagegruen.org/vgforum/index.php?t=finduser&btn_submit=Find&

http://immigrantentrepreneurship.org/entry.php?rec=219

http://www.gruenwristwatches.com/new-dating-method-2.php

http://www.glashuetteuhren.de/die-uhrenfabriken/j-assmann-glashuette-i-sa-deutsche-anker-uhren-fabrik-1/gruenschen-uhrenfabrikation-gruen-und-assmann/

http://vintagewatchforums.com/viewforum.php?f=33

http://www.thewatchguy.com/pages/GRUEN.html

http://www.pixelp.com/gruen/

http://gruen.watch/?page_id=209

http://www.pocketwatchrepair.com/railroad.html

http://www.watchesoftheguild.com/gruen-tank.html