Perhaps you should try some spelling variations:
mittelbau » mittelbach
mittelbar » unmittelbar, ermittelbar
unmittelbare » ununmittelbare, unermittelbare, unmittelbar, ermittelbar
mittelbare » unmittelbare, ermittelbare
unmittelbaren » ununmittelbaren, unermittelbaren, unmittelbarn, ermittelbarn, unmittelbar

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 unmittelbare) OR mittelbare)) OR unmittelbaren).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((mittelbau or ((mittelbar OR unmittelbare) or mittelbare)) or unmittelbaren)".
• Adding a wildcard symbol may retrieve word variants: ((mittelbau or ((mittelbar OR unmittelbare) or mittelbare)) or unmittelbaren)*.