Perhaps you should try some spelling variations:
helman ebooks » german books
hermann book » german book, hermann broch, hermann von
hermann lohr » hermann der, hermann von
gal robert » hall robert
robert j » robert _, robert e
a robust » _ robust
robust e » robust _, robust a, robust end

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: (( gal robert j. ((hermann book) OR (hermann lohr)) ) OR ( a robust e. helman ebooks ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( gal robert j. ((hermann book) OR (hermann lohr)) ) or ( a robust e. helman ebooks ))~".
• Adding a wildcard symbol may retrieve word variants: (( gal robert j. ((hermann book) OR (hermann lohr)) ) or ( a robust e. helman ebooks ))*.