Perhaps you should try some spelling variations:
black robert » blair robert, banick robert, bacon robert
robert j » robert _
robert e » robert _
heilman » hellman, heitmann
heilmann » hellmann, heitmannn, heimann, heitmann, heinemann
book » books, ebook
eebooks » eebookss, eeebooks, ebooks

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( black robert j. (heilman OR heilmann) book ) or ( _ robert e. hermann eebooks ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( black robert j. (heilman OR heilmann) book ) OR ( _ robert e. hermann eebooks ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( black robert j. (heilman OR heilmann) book ) or ( _ robert e. hermann eebooks ))*".