Perhaps you should try some spelling variations:
robert j » robert _
a robert » a robust
robert e » robert _
gal » goal, gael, gail
book » books, ebook
ebookss » ebooksss, eebookss
eebookss » eebooksss, eeebookss
ebooks » ebookss, eebooks
heitmann » heimann, heinemann, hartmann

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

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