Perhaps you should try some spelling variations:
gail robert » gal robert, davis robert, blair robert
robert b » robert _, robert e, robert j
a robust » _ robust
book » books, ebook
ebooks » ebookss, eebooks
eebooks » eebookss, eeebooks
heitmann » heinemann, hartmann
heimann » heinemann

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( gail robert b. hermann book ) or ( a robust _. (heitmann or heimann) (ebooks OR eebooks) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( gail robert b. hermann book ) OR ( a robust _. (heitmann OR heimann) (ebooks OR eebooks) ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( gail robert b. hermann book ) or ( a robust _. (heitmann or heimann) (ebooks OR eebooks) ))*".