In Hoffmann Band II, Teil 1 p. 413 there is a passage that many of have read many times and wondered. It is part of an excellent memorandum prepared by II JK:
Der Bunker Cäsar ist ein Korps- und Divisions Gefechtsstand mit einem Betonvolumen von 4000 cbm Beton und einer Rohbauzeit von 3 Monaten.
When the GefStd bunkers of II JK and 5 JD "blossomed" in a more widespread audience I started to wonder again. The feeling of being on to something, was reinforced when the GefStd of I JK was found in Treuenbrietzen. The bunkers of II JK and 5 JD are almost identical, and the bunker of I JK has a great Look-Alikeness - judging from the one know photo, even the chimneys are similar.
Please see:
http://www.gyges.dk/Type%20Caesar.htm
bregds
SES