Perhaps you should try some spelling variations:
heimann books » demand books, german books
goal robert » gal robert, fogel robert, goal poverty
deal robert » dekle robert, gal robert, dahl robert
a robert » 3 robert, dr robert, a robust
robert e » robert _, robert j
ebooks » 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: (( ((goal robert) OR (deal robert)) _. heimann books ) or ( a robert e. heimann ebooks ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( ((goal robert) OR (deal robert)) _. heimann books ) OR ( a robert e. heimann ebooks )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( ((goal robert) OR (deal robert)) _. heimann books ) or ( a robert e. heimann ebooks ))".
• Adding a wildcard symbol may retrieve word variants: (( ((goal robert) OR (deal robert)) _. heimann books ) or ( a robert e. heimann ebooks ))*.