Perhaps you should try some spelling variations:
hartmann book » hartmann sonke, hartmann von
hermann broch » hermann brochs
hermann book » german book, hermann lohr, hermann von
a robust » _ robust
robust j » robust _, robust a, robust job
a robert » 3 robert, dr robert, a robot
robert e » robert _, robert j

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( a robust j. hartmann book ) or ( a robert e. ((hermann book) OR (hermann broch)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( a robust j. hartmann book ) OR ( a robert e. ((hermann book) OR (hermann broch)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( a robust j. hartmann book ) or ( a robert e. ((hermann book) OR (hermann broch)) ))".
• Adding a wildcard symbol may retrieve word variants: (( a robust j. hartmann book ) or ( a robert e. ((hermann book) OR (hermann broch)) ))*.