Perhaps you should try some spelling variations:
heimann books » demand books, german books
a robert » 3 robert, dr robert, a robust
robert j » robert _
robert e » robert _
robert b » robert _, robert a
heilmann » heilemann, heitmann, heilman
book » ebook
books » ebooks

You may be able to get more results by adjusting your search query.

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