Perhaps you should try some spelling variations:
gail robert » gal robert, davis robert, blair robert
robert j » robert _, robert e
a robust » _ robust
heilmann » heinemann, hellman, heymann
heimann » heinemann
book » books
ebook » ebooks
heitmann » 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: (( gail robert j. (heilmann or (heimann OR hermann)) book ) or ( a robust _. heitmann ebook ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( gail robert j. (heilmann OR (heimann OR hermann)) book ) OR ( a robust _. heitmann ebook )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( gail robert j. (heilmann or (heimann OR hermann)) book ) or ( a robust _. heitmann ebook ))".
• Adding a wildcard symbol may retrieve word variants: (( gail robert j. (heilmann or (heimann OR hermann)) book ) or ( a robust _. heitmann ebook ))*.