Perhaps you should try some spelling variations:
gail robert » hall robert, ball robert, dahl robert
gal robert » hall robert
robert e » robert _, robert j
a robert » 3 robert, dr robert, a robust
heilmann » heilemann, heitmann, heilman
book » ebook
books » ebooks
ebooks » eebooks, ebook, redbooks, texbooks

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 e. heilmann (book OR books) ) or ( ((a robert) or (gal robert)) _. heimann ebooks ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( gail robert e. heilmann (book OR books) ) OR ( ((a robert) OR (gal robert)) _. heimann ebooks )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( gail robert e. heilmann (book OR books) ) or ( ((a robert) or (gal robert)) _. heimann ebooks ))".
• Adding a wildcard symbol may retrieve word variants: (( gail robert e. heilmann (book OR books) ) or ( ((a robert) or (gal robert)) _. heimann ebooks ))*.