Perhaps you should try some spelling variations:
mittelbau » mittelbare, mittelbach
mittelbar » mittelbare, unmittelbar, unmittelbare
ermittelbar » ermittelbare, erunmittelbar, erunmittelbare, unmittelbar, unmittelbare
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 ermittelbar) OR mittelbisau).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((mittelbau OR mittelbar) or ermittelbar) or mittelbisau)".
• Adding a wildcard symbol may retrieve word variants: (((mittelbau OR mittelbar) or ermittelbar) or mittelbisau)*.