Perhaps you should try some spelling variations:
mittelbau » mittelbach
mittelbar » unmittelbar, unmittelbare
mittelbare » unmittelbare, unmittelbaree, unmittelbaren
ermittelbar » erunmittelbar, erunmittelbare, unmittelbar
mittelbisau » mittelbis

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((((mittelbau OR mittelbar) OR mittelbare) OR ermittelbar) OR mittelbisau).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((mittelbau OR mittelbar) or mittelbare) or ermittelbar) or mittelbisau)".
• Adding a wildcard symbol may retrieve word variants: ((((mittelbau OR mittelbar) or mittelbare) or ermittelbar) or mittelbisau)*.