Perhaps you should try some spelling variations:
gail robert » gal robert, davis robert, blair robert
robert j » robert _, robert e
robust e » robust _, robert e
heitmann » heinemann, hermann, hartmann
book » ebook
books » ebooks
eebooks » eeebooks, ebooks
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 ( _ robust e. (heilmann or heimann) eebooks ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( gail robert j. heitmann (book OR books) ) OR ( _ robust e. (heilmann OR heimann) eebooks )).
• Adding a wildcard symbol may retrieve word variants: (( gail robert j. heitmann (book or books) ) or ( _ robust e. (heilmann or heimann) eebooks ))*.