Perhaps you should try some spelling variations:
"johannes dieter muller" » "johannes dietlein muller", "johannes pfister muller", "johannes richter muller", "johannes dietmar muller", "johannes peter muller", "johannes gunter muller"
"johannes carol mullen" » "johannes carl mullen", "johannes carson mullen", "johannes maron mullen", "johannes carol miller", "johannes carol turley"

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: (("johannes carol mullen") OR ("johannes dieter muller")).
• Removing quotes may allow a broader search: (( johannes carol mullen ) or ( johannes dieter muller )).
• Adding a wildcard symbol may retrieve word variants: (("johannes carol mullen") or ("johannes dieter muller"))*.