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