Perhaps you should try some spelling variations:
fogel robert » jovel roberto, fimbel robert, wrobel robert
hermann book » german book, hermann broch, hermann lohr
goal robert » gal robert, deal robert, goal poverty
a robust » _ robust
heitmann » heimann, heinemann, hartmann
eeebooks » redbooks, ebooks, texbooks

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: (( ((goal robert) OR (fogel robert)) j. hermann book ) OR ( a robust _. heitmann eeebooks ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((goal robert) OR (fogel robert)) j. hermann book ) or ( a robust _. heitmann eeebooks ))~".
• Adding a wildcard symbol may retrieve word variants: (( ((goal robert) OR (fogel robert)) j. hermann book ) or ( a robust _. heitmann eeebooks ))*.